5
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Use any programming language to generate two random digits between 1 and 9 (including both). Then your program should display:

  • in the first line: the first random digit,
  • in the second line: the second random digit,
  • in the third line: a number whose tens and units digits are the first and second random digits respectively,
  • in the fourth line: the number from the third line raised to the power of 2.

For example, if digits "9" and "2" were generated, your program should display exactly:

9
2
92
8464
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  • 12
    \$\begingroup\$ Can we output an array? \$\endgroup\$ – Quintec Oct 31 '18 at 11:57
  • 3
    \$\begingroup\$ Can we sample without replacement, ie exclude 1,1 2,2 3,3... from the pairs? \$\endgroup\$ – JayCe Oct 31 '18 at 13:57
  • 2
    \$\begingroup\$ (i.e., what's the distribution of the random numbers?) \$\endgroup\$ – user202729 Oct 31 '18 at 16:11
  • \$\begingroup\$ You should probably specify that the digits are pairwise independent and uniformly random. Otherwise, one can go with a degenerate distribution and write "cat (10 Bytes): 1[newline]1[newline]11[newline]121" \$\endgroup\$ – Yonatan N Nov 2 '18 at 0:23
  • \$\begingroup\$ @YonatanN The standard assumption on PPCGcfor the term random is that all possibilities have a non-zero chance of occuring. \$\endgroup\$ – Jo King Nov 2 '18 at 12:47

29 Answers 29

2
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05AB1E, 14 11 bytes

2F9LΩ=}J=n,

-3 bytes thanks to @Emigna.

Try it online.

Explanation:

2F    }        # Loop 2 times:
  9LΩ          #  Create a list in the range [1,9], and pick a random element from it
     =         #  Output it (without popping it from the stack)
       J       # Join them together
        =      # Output it (without popping it from the stack)
         n     # Take it to the power of 2
          ,    # And output it as well

11 bytes alternative:

9LãΩ©`®JDn»

Try it online.

Explanation:

9L             # List in the range [1,9]
  ã            # Cartesian product with itself: [[1,1],[1,2],[1,3],...,[9,7],[9,8],[9,9]]
   Ω           # Take a random element from it
    ©          # Store it in the register (without popping)
     `         # Pop and push both items as separated items onto the stack
      ®        # Retrieve the list of digits from the register again
       J       # Join them together to a single 2-digit number
        Dn     # Duplicate it, and take the power of 2 of the copy
          »    # Merge all values on the stack by newlines (and output implicitly)
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  • 1
    \$\begingroup\$ Shorter in a looP: 2F9LΩ=}J=n, \$\endgroup\$ – Emigna Oct 31 '18 at 12:01
  • \$\begingroup\$ @Emigna I was about to look for shorter alternatives, but smart use of the =! \$\endgroup\$ – Kevin Cruijssen Oct 31 '18 at 12:04
6
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R, 48 47 bytes

cat(x<-sample(9,2,T),y<-x%*%c(10,1),y^2,fill=1)

Try it online!

Thanks to J.Doe for golfing down a byte.

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  • \$\begingroup\$ Tweak to cat args. 47 bytes \$\endgroup\$ – J.Doe Nov 3 '18 at 19:24
  • \$\begingroup\$ @J.Doe thanks! Probably there are other submissions where fill would be handy... \$\endgroup\$ – Giuseppe Nov 3 '18 at 22:32
5
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Japt, 14 13 bytes

-1 Byte from @Oliver

2ÆÒ9ö
pU¬Uì ²

2ÆÒ9ö
pU¬Uì ²     Full program
-----------------------------------------
2Æ            Range [0,2) and map 
   9ö         Random number in range [0, 9)
  Ò           increased by 1
              This result is assigned to U

p            Push into U    
 U¬          Elements in U joined
   Uì ²      and elements joined squared
             Implicit output each element 
             separated with new line -R

Try it online!

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  • 1
    \$\begingroup\$ You can use 2ÆÒ9ö to save a byte on the first line. \$\endgroup\$ – Oliver Oct 31 '18 at 17:33
5
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Vim, 43 bytes

:%!$RANDOM

:s/0//g
2f:y2hVpo<C-r>=<C-r>0*<C-r>0
<Esc>kYPa

Try it online!

Not the right tool for the job. This produces most likely the desired output

Step by step:

  • :%!$RANDOM Enter Enter
    Produces a string like /bin/bash: 25266: command not found

  • :s/0//g
    removes all zeroes

  • 2f:y2hVp
    moves the cursor to the colon after the number, copy the last two digits and replace the entire string with those

  • o Ctrl+R = Ctrl+R 0* Ctrl+R 0 Enter
    add a new line and evaluate an expression. In this case, I'll multiply the number in register 0 (the one that was just copied) with itself.

  • Esc kYPa Enter
    Copy the upper line and paste it above. The cursor ends up in the first line, on the first character. Now we just have to append a line break to it

Limitations: If the result of $RANDOM is a number with less than two non-zero digits, this will not produce the desired output

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4
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C (gcc), 68 67 bytes

-1 byte thanks to cleblanc

f(r){r=rand()%81*10/9+11;printf("%d\n%d\n%d\n%d",r/10,r%10,r,r*r);}

Try it online!

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  • \$\begingroup\$ save one byte using r;f() --> f(r) \$\endgroup\$ – cleblanc Oct 31 '18 at 13:10
4
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K (oK), 28 bytes

t:2?10;t,:10/t;$t,:t[2]*t[2]

Explanation

t:2?10                       //define t as two random numbers from 1-10
       t,:10/t               //join the base 10 joining of the elements of t to t
                 t,:t[2]*t[2]//join the square of the index 2 element to t
               $            //String each element of the result (to output on newlines)

Try it online!

Cleaner Output, 32 bytes

t:2?10;t,:10/t;`0:$t,:t[2]*t[2];

               `0:               //Cleanly prints the strings

Try it online!

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  • 1
    \$\begingroup\$ If we're allow to return an array then a,b,b*b:10/a:1+2?9 for 18 chars Try it online! \$\endgroup\$ – streetster Oct 31 '18 at 19:00
  • \$\begingroup\$ +1 Much neater, its only the extra $ character to match the output of my first answer, with -9 bytes. I hadn't tried to fit it into one expression \$\endgroup\$ – Thaufeki Oct 31 '18 at 19:34
  • \$\begingroup\$ 2?10 could generate a 0. the challenge requires 1-9. \$\endgroup\$ – ngn Nov 1 '18 at 7:05
  • 2
    \$\begingroup\$ `0:$a,*\2#10/a:1+2?9; (works in ngn/k too) \$\endgroup\$ – ngn Nov 1 '18 at 7:09
  • 1
    \$\begingroup\$ @Thaufeki the random seed in ngn/k predetermined, like in the original k \$\endgroup\$ – ngn Dec 4 '18 at 9:57
3
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Perl 6, 39 bytes

{.comb,$_,$_²}([~] roll 1..9: 2)>>.put

Try it online!

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3
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JavaScript (ES6), 67 bytes

f=_=>(n=Math.random()*90+10|0)%10?(n/10|0)+`
${n%10}
${n}
`+n*n:f()

Try it online!

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3
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Pyth, 14 bytes

^
i,
hO9
hO9T2

Note that the newlines are significant. Try it online here.

Explanation, with newlines replaced with ¶ character:

^¶i,¶hO9¶hO9T2   Implicit: T=10

      O9         Choose a random number in [0-9)
     h           Increment
    ¶            Output with newline - value printed is yielded as expression result
        ¶hO9     Do the above again
   ,             Wrap the two previous results in a two-element array
  i         T    Convert to decimal from base 10
 ¶               Output with newline
^            2   Square the previous result, implicit print
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  • 2
    \$\begingroup\$ @Downvoter - any particular reason why? \$\endgroup\$ – Sok Oct 31 '18 at 14:47
3
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Jelly, 10 9 bytes

9ṗ2XṄ€ḌṄ²

Try it online!

How it works

9ṗ2XṄ€ḌṄ²  Main link. No arguments.

9          Set the return value to 9.
 ṗ2        Promote 9 to [1, ..., 9] and take the second Cartesian power, yielding
           [[1, 1], [1, 2], ..., [9, 8], [9, 9]].
   X       Pseudo-randomly select one of the pairs.
    Ṅ€     Print each integer in the pair, followed by a newline.
      Ḍ    Undecimal; convert the integer pair from base 10 to an integer.
       Ṅ   Print the integer, followed by a newline.
        ²  Take the square.
           (implicit) Print the last return value.
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3
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Ruby, 41 bytes

puts [(a=11+10*rand(81)/9)/10,a%10,a,a*a]

Try it online!

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3
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T-SQL, 142 105 115 114 96 78 bytes

DECLARE @ int=RAND()*9+1,@a int=RAND()*9+1SELECT @,@a,10*@+@a,POWER(10*@+@a,2)

-37 bytes: Realized I could just use two different random numbers and use the first digits from each!
+10 bytes: Edited to meet requirements of range from 1-9, instead of 0-9
-1 byte: Changed RIGHT() to LEFT() in @b
-18 bytes: Various changes suggested by BradC
-18 bytes: More changes suggested by BradC

Ungolfed:

-- Setting RAND() separately in these produces different numbers.
-- [RAND() * b + a] sets the range for a random number, from a to b inclusive.
-- Declaring as an int removes the numbers after the decimal.
DECLARE @ int = RAND() * 9 + 1,
        @a int = RAND() * 9 + 1

SELECT @,                       -- first random digit
       @a,                      -- second random digit
       10 * @ + @a,             -- multiply first digit by ten, and add second
       POWER(10 * @ + @a, 2)    -- third digit squared
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  • \$\begingroup\$ The stuff in the first comment definitely works, I'll edit that in. Problem with making the variables ints is that I would need to cast each individually as chars in the SELECT where necessary. With that, since each variable would need to be converted twice (in @+@a and POWER(@+@a,2)), it'd add more characters than it would save. \$\endgroup\$ – Meerkat Oct 31 '18 at 15:43
  • \$\begingroup\$ Good calls, thanks. Don't know why I didn't think of multiplying the first number by ten... \$\endgroup\$ – Meerkat Oct 31 '18 at 17:51
  • \$\begingroup\$ No problem, I'll delete my comments since you've incorporated them. \$\endgroup\$ – BradC Oct 31 '18 at 18:20
3
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Python 3, 83 76 bytes

-5 bytes thanks to nwellnhof.

from random import*
k=randint(9,89)*10//9+1
[*map(print,[k//10,k%10,k,k*k])]

Try it online!

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3
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PowerShell, 48 45 bytes

($a,$b=1..9*2|Random -c 2)
($x="$a$b")
+$x*$x

Try it online!

Concatenates two ranges 1..9 together, pipes that to Get-Random with a -count of 2 to pull out two elements, stores them into $a and $b, and encapsulates that in parens to place a copy of them on the pipeline.

Next we string concatenate $a$b and store it into $x, again placing in parens to put a copy on the pipeline. Finally we take $x squared and leave it on the pipeline.

All the results are gathered from the pipeline and an implicit Write-Output gives us newlines between elements for free.

Saved 3 bytes thanks to mazzy.

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  • 1
    \$\begingroup\$ Smart get-random \$\endgroup\$ – mazzy Oct 31 '18 at 14:07
  • \$\begingroup\$ I think 1..9|Random -c 2 completely satisfies the condition two random digits between 1 and 9 (including both) \$\endgroup\$ – mazzy Nov 1 '18 at 11:22
  • \$\begingroup\$ ...if not, then 1..9*2 is shorter \$\endgroup\$ – mazzy Nov 1 '18 at 11:25
  • 1
    \$\begingroup\$ @mazzy Other answers seem to pick the two digits with replacement, so I did so as well. Thanks for the 1..9*2 golf! \$\endgroup\$ – AdmBorkBork Nov 2 '18 at 12:31
2
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Charcoal, 16 bytes

≔⭆²⊕‽⁹θ↓θθ⸿IXIθ²

Try it online! Link is to verbose version of code. Explanation:

≔⭆²⊕‽⁹θ

Generate two random characters in the range 1 to 9.

↓θ

Output them downwards i.e. on separate lines.

θ⸿

Output them horizontally on their own line.

IXIθ²

Cast to integer, square, cast back to string for implicit print.

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2
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Java 8, 99 98 90 81 80 bytes

v->{int i=81;i*=Math.random();return(i=i*10/9+11)/10+"\n"+i%10+"\n"+i+"\n"+i*i;}

-8 bytes after being inspired by @Arnauld's JavaScript answer.
-9 bytes thanks to @nwellnhof.

Try it online.

Explanation:

v->{                        // Method with empty unused parameter and no return-type
  int i=81;i*=Math.random();//  Create a random integer `i` in the range [0,81)
  return(i=i*10/9+11)       //  Set `i` to 10 times `i`, integer-divided by 9, and 11 added
        /10+"\n"            //  Return the first digit of `i`, a newline,
        +i%10+"\n"          //         the last digit of `i`, a newline,
        +i+"\n"             //         `i` itself, a newline,
        +i*i;}              //         and `i` multiplied by itself
                            //         All concatted to each other
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2
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Python 2, 84 75 bytes

from random import*
k=randint(9,89)*10/9+1
for x in k/10,k%10,k,k*k:print x

Try it online!


Saved

  • -1 bytes, thanks to Erik the Outgolfer
  • -8 bytes, thanks to nwellnhof
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  • \$\begingroup\$ Moderate golf: 83 bytes. \$\endgroup\$ – Erik the Outgolfer Oct 31 '18 at 14:03
  • \$\begingroup\$ @EriktheOutgolfer Thanks :) \$\endgroup\$ – TFeld Oct 31 '18 at 15:10
2
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C# (.NET Core), 130 129 109 98 bytes

var r=new Random();int a=r.Next(1,10),b=r.Next(1,10),c=a*10+b;Console.Write($"{a} {b} {c} {c*c}");

Try it online!

-1 byte: edited console output to use wildcards (thanks to Logern)
-20 bytes: changed r to var from Random, changed format of c; fixed r.Next() operators (thanks to LiefdeWen)
-11 bytes: changed format of c (thanks to user51497)

Ungolfed:

var r = new Random();                   // initializes random number generator
int a = r.Next(1, 10),                  // gets random number between 1 and 9 inclusive
    b = r.Next(1, 10),                  // gets random number between 1 and 9 inclusive
    c = a * 10 + b;                     // concatenates a and b into one two-digit number
Console.Write($"{a} {b} {c} {c*c}");    // writes a, b, c, and c^2 to the console
\$\endgroup\$
  • \$\begingroup\$ 129 bytes-Try it online! \$\endgroup\$ – Logern Oct 31 '18 at 16:57
  • 1
    \$\begingroup\$ 109 bytes Also your .Next needs to include 10 so it can random 9 \$\endgroup\$ – LiefdeWen Nov 1 '18 at 12:54
  • \$\begingroup\$ @LiefdeWen Thanks. Didn't realize the max value of Random.Next() was exclusive. The min value is inclusive, though, so that needs to stay at 1 to fit the requirement of being between 1-9 inclusive. \$\endgroup\$ – Meerkat Nov 1 '18 at 13:07
  • 1
    \$\begingroup\$ -11 bytes c = a*10 + b; \$\endgroup\$ – user51497 Nov 1 '18 at 15:57
  • 2
    \$\begingroup\$ This looks to be a snippet rather than a full function or program. Here is the guide to C# that should be able to help you turn your snippet into an acceptable answer. \$\endgroup\$ – AdmBorkBork Nov 9 '18 at 13:56
1
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TI-BASIC, 27 bytes

11+int(89rand
Disp iPart(.1Ans),10fPart(.1Ans),Ans,Ans²

(can generate a 0 in the 2nd random number)

Uses kamoroso94's Disp layout, but makes use of TI-BASIC integer compression. Generating the 2 random integers as a single compressed integer and extracting them via iPart and fPart allows for shaving several bytes. It's possible to generate the random integers seperately in the same number of bytes by creating them simultaneously in a list:

1+int(9rand(2

But the repeated calls to the list via Ans(1) and Ans(2) end up taking many more bytes than the integer compression technique. It's also important to note that rand is generally advisable over randInt( for random integer generation as they either use equivalent bytes, or rand will be shorter when the lower bound is 0, and rand has the added flexibility of list generation.

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  • \$\begingroup\$ This doesn't work; sometimes it generates 0 for the second digit. \$\endgroup\$ – lirtosiast Nov 11 '18 at 1:41
  • \$\begingroup\$ Yeah I see what I missed now, I don't think it's possible to improve from the 31 bytes and avoid the zeros then without messing with the output formatting. You can get 33 bytes by adding 2 randInt() and extracting them as shown here or 33 bytes again via the random list. \$\endgroup\$ – TiKevin83 Nov 12 '18 at 22:00
0
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PHP, 64 bytes

<?$d=($c=(10*($a=rand(1,9))+$b=rand(1,9)))*$c;echo"$a
$b
$c
$d";

Try it online!

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0
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Retina, 43 bytes


100*
L$`
$.`
A`0
G?`..
\*\L`.
..
$.($&*$&*

Try it online! Explanation:


100*
L$`
$.`

Count from 0 to 99.

A`0

Delete multiples of 10.

G?`..

Pick a random 2-digit number.

*\L`.

Output the digits separately.

\

Output the number.

..
$.($&*$&*

Square and implicitly output the number.

\$\endgroup\$
0
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TI-BASIC, 31 bytes

randInt(1,9→A
randInt(1,9→B
10A+B
Disp A,B,Ans,Ans²
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0
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MBASIC, 100 86 bytes

1 DEF FNR(X)=INT(RND*X)+1:A=FNR(9):B=FNR(9):PRINT A:PRINT B:C=A*10+B:PRINT C:PRINT C^2

Output

5
8
58
3364
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0
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sfk, 99 bytes

rand 1 9 +setvar a +rand 1 9 +setvar b +tell -var "#(a)
#(b)
#(a)#(b)" +calc -var #(a)#(b)*#(a)#(b)

Try it online!

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0
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perl -E, 45 bytes

$_=10+int rand 90;y/0/1/;say for/./g,$_,$_**2

This exploits the lack of a requirement that all random numbers should be picked with equal probability (it will pick numbers ending in 1 twice as often as ending in any other digit).

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0
\$\begingroup\$

Visual C#, 102 Bytes; 101 bytes

+2 Upper bound of Random.Next() exclusive, 10 instead of 9
-3 Thanks to LiefdeWen (var instead of Random)

var r=new Random();int x=r.Next(1,10),y=r.Next(1,10),z=x*10+y;Console.Write($"{x}\n{y}\n{z}\n{z*z}");

normal form:

var r = new Random();
int x = r.Next(1, 10), 
    y = r.Next(1, 10), 
    z = x * 10 + y;
Console.Write($"{x}\n{y}\n{z}\n{z * z}");

Try it online!

Visual C#, 85 bytes 89 bytes 91 Bytes

+4 bytes: fixed problem with 0 as second digits, borrowing the *10/9+1 from other answers

+2 bytes: preventing numbers <11

Even shorter solution

var r=new Random();int x=r.Next(9,89)*10/9+1;Console.Write($"{x/10}\n{x%10}\n{x}\n{x*x}");

normal form:

var r = new Random();
int x = r.Next(9, 89)*10/9+1;
Console.Write($"{x/10}\n{x%10}\n{x}\n{x*x}");

Try it online!

\$\endgroup\$
  • \$\begingroup\$ 98 bytes. You also had to include 10 in .Next to make 9 possible \$\endgroup\$ – LiefdeWen Nov 1 '18 at 12:51
0
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Red, 69 bytes

prin reduce[x: random 9 n:"^/"y: random 9 n z: do rejoin[x y]n z * z]

Try it online!

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0
\$\begingroup\$

Batch, 95 bytes

@set/at=%random%%%9+1,u=%random%%%9+1,n=t*10+u,p=n*n
@for %%a in (%t% %u% %n% %p%)do @echo %%a

%random% isn't a real variable, it's interpolated at parse time, so you need the %s even inside set/a. (Also don't try using it in a loop!)

\$\endgroup\$
0
\$\begingroup\$

MathGolf, 9 bytes

2æ8w)o§o²

Try it online!

Explanation

For the example, the first random integer is 4, the second is 7.

2æ         Start for-loop of length two, with the next 3 chars as the body
  8w       Random non-negative integer less than or equal to 8
    )      Increment by 1
     o     Output without popping (stack is unchanged)
           For loop ends, stack is now [4, 7], the first two lines have been printed
     §     Concatenate the two numbers on the stack (stack is [47])
      o    Output without popping (stack is unchanged)
       ²   Square number and output implicitly
\$\endgroup\$

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