Questions tagged [math]

The challenge involves mathematics. Also consider using more specific tags: [number] [number-theory] [arithmetic] [combinatorics] [graph-theory] [geometry] [abstract-algebra].

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-2
votes
2answers
153 views

find the value at kth position when numbers are sorted lexicographically till n [closed]

Ex :- Input: n = 12, k = 5 Output: ans = 2 Sorted list S: ["1", "10", "11", "12", "2", "3", "4", "5", ...., "9"] ans = 2
1
vote
4answers
202 views

Round the digits last digit, over and over

Challenge: Given two inputs, x and y, round x to one less significant figure, then repeat until it has y number of unrounded digits left. (the decimal point does not count as a digit) Input & ...
18
votes
31answers
5k views

Find the number of leading zeroes in a 64-bit integer

Problem: Find the number of leading zeroes in a 64-bit signed integer Rules: The input cannot be treated as string; it can be anything where math and bitwise operations drive the algorithm The ...
13
votes
1answer
1k views

Golf a number bigger than Loader's number

As a follow up to Shortest terminating program whose output size exceeds Graham's number and Golf a number bigger than TREE(3), I present a new challenge. Loader's number is a very large number, ...
21
votes
26answers
2k views

Digital Sumorial

Given an input n, write a program or function that outputs/returns the sum of the digital sums of n for all the bases 1 to ...
25
votes
6answers
1k views

Prime containment numbers (speed edition)

This is sequence A054261 The \$n\$th prime containment number is the lowest number which contains the first \$n\$ prime numbers as substrings. For example, the number \$235\$ is the lowest number ...
21
votes
14answers
2k views

Prime containment numbers (golf edition)

This is sequence A054261. The \$n\$th prime containment number is the lowest number which contains the first \$n\$ prime numbers as substrings. For example, the number \$235\$ is the lowest number ...
20
votes
38answers
2k views

Given an input, print all exponents where the base and power sum to the input

So this is my first challenge on this site. The challenge is to take in an input integer \$n\$, which will be positive, and print, in ascending order (\$1\$ to \$n\$, including n), the output of \$i^{...
11
votes
3answers
408 views

Is it an arithmetico-geometric sequence?

An arithmetico-geometric sequence is the elementwise product of an arithmetic sequence and a geometric sequence. For example, 1 -4 12 -32 is the product of the ...
-4
votes
1answer
270 views

Compound interest with additions [closed]

You have been given the charge to calculate the current balance as of the day that you perform the calculation for 330,000 individuals who worked for an average of 30 years spanning 300 years where ...
18
votes
8answers
780 views

Is this quadrilateral cyclic?

In mathematics, a cyclic quadrilateral is one whose vertices all lie on the same circle. In other words, every vertex is on the circumcircle of the other three. For more information, see the MathWorld ...
19
votes
13answers
1k views

Dirichlet Convolution

The Dirichlet convolution is a special kind of convolution that appears as a very useful tool in number theory. It operates on the set of arithmetic functions. Challenge Given two arithmetic ...
12
votes
11answers
2k views

Quaternion square root

Background Quaternion is a number system that extends complex numbers. A quaternion has the following form $$ a + bi + cj + dk $$ where \$ a,b,c,d \$ are real numbers and \$ i,j,k \$ are three ...
19
votes
27answers
3k views

Strange Addition

Challenge Calculate the strange sum of two natural numbers (also known as lunar addition): Given A=... a2 a1 a0 and ...
14
votes
27answers
2k views

The inverse Collatz Conjecture

I think the Collatz Conjecture is already well-known. But what if we invert the rules? Start with an integer n >= 1. Repeat the following steps: If n is even, multiply it by 3 and add 1. If n is ...
15
votes
40answers
2k views

Sum square difference

The sum of the squares of the first ten natural numbers is, \$1^2 + 2^2 + \dots + 10^2 = 385\$ The square of the sum of the first ten natural numbers is, \$(1 + 2 + ... + 10)^2 = 55^2 = 3025\$ ...
0
votes
0answers
60 views

Multiples of 3 or 5 [duplicate]

If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3, 5, 6 and 9. The sum of these multiples is 23. For a given input n, find the sum of multiples of 3 or five between 1 ...
0
votes
4answers
446 views

Fastest algorithm to output array containing all integers in range excluding duplicate digits

Input is a single integer in ascending digit order. The only valid inputs are: 12 123 1234 ...
14
votes
6answers
1k views

Ryley's Theorem

S. Ryley proved following theorem in 1825: Every rational number can be expressed as a sum of three rational cubes. Challenge Given some rational number \$r \in \mathbb Q \$ find three rational ...
3
votes
0answers
125 views

Number of circles packed into a rectangle [closed]

Calculate the maximum number of circles of radius r that can fit in a rectangle with width x and height ...
9
votes
5answers
205 views

Find the minimal initial values [duplicate]

Consider a sequence F of positive integers where F(n) = F(n-1) + F(n-2) for n >= 2. The ...
2
votes
0answers
237 views

Find the pattern

I feel tired to do "find the pattern" exercise such as 1 2 3 4 (5) 1 2 4 8 (16) 1 2 3 5 8 (13) Please write a program that finds the pattern for me. Here, we ...
17
votes
28answers
1k views

Given a string, calculate the number of the column it corresponds to

In Excel, the columns range from A-Z, AA,AB,AZ,BA,..,BZ and so on. They actually each stand for numbers, but rather are encoded as alphabet strings. In this ...
7
votes
5answers
300 views

Multiply numerical polynomials

A numerical polynomial is a polynomial \$p\$ in one variable with rational coefficients such that for every integer \$i\$, \$p(i)\$ is also an integer. The numerical polynomials have a basis given by ...
8
votes
0answers
134 views

Find a way to determine to which fibonacci squares a given coordinate belongs [closed]

Given a random coordinate (x,y), determine in which square (squares are referenced by their sidelength) it is (or the borders of which squares). The squares are drawn in a counter clockwise direction,...
-3
votes
5answers
76 views

Concatenate 2 numeric type values to a fixed size number [closed]

You have 2 numbers, both stored separate as numeric data type. First number is always 6 digits long. Second number can vary between 1 and 4 digits. If it's less than 4 digits, it needs to be padded ...
19
votes
12answers
2k views

Is the Matrix Positive-Definite?

Introduction Today we're gonna take care of the bane of first-year linear algebra students: matrix definiteness! Apparently this doesn't yet have a challenge so here we go: Input A \$n\times n\$ ...
4
votes
3answers
191 views

Hyperoperation Golfing [duplicate]

Introduction In mathematics, the hyperoperation sequence is an infinite sequence of arithmetic operations (called hyperoperations) that starts with the unary operation of successor (n = 0), then ...
5
votes
0answers
282 views

What is the simplest reversible circuit that computes conjugacy of transpositions?

Reversible computation refers to computation in which little or no information is deleted. Reversible computation a major component of quantum computation, and reversible computation is potentially ...
8
votes
11answers
328 views

Cayley Table of the Dihedral Group \$D_3\$

The Dihedral group \$D_3\$ represents the symmetries of an equilateral triangle, using the identity (represented by id), rotations (represented by ...
17
votes
39answers
1k views

Sum \$\text{Square}^2\$

Let \$n=42\$ (Input) Then divisors are : 1, 2, 3, 6, 7, 14, 21, 42 Squaring each divisor : 1, 4, 9, 36, 49, 196, 441, 1764 Taking sum (adding) : 2500 Since \$50\times 50=2500\$ therefore we return ...
0
votes
0answers
134 views

Make n n n n = x [duplicate]

Background So I've been inspired by this puzzleing SE question to create a similar Code Golf challenge. The basic puzzle format is you must use 4 numbers, such as 5 5 5 5, to equal some other number, ...
7
votes
20answers
430 views

Find the \$\left(n^2\right)^\text{th }n\$-gonal number

Given a non-negative integer, \$n\$, yield the \$(n^2)^\text{th } n\$-gonal number. Further Detail: The \$x\$-gonal numbers, or polygonal numbers, are also known as the two-dimensional figurate ...
20
votes
17answers
3k views

How many cubes can be built

task Your task is to build a structure with \$n\$ cubes. The volume of cubes follow the following sequence (bottom -> top) \$n^3, (n-1)^3, (n-2)^3,...,1^3\$ input The total volume of the ...
24
votes
14answers
1k views

Number Spiral Problem

A number spiral is an infinite grid whose upper-left square has number 1. Here are the first five layers of the spiral: Your task is to find out the number in row y and column x. Example: ...
12
votes
17answers
510 views

Compute the minimum \$a(n)>a(n-1)\$ such that \$a(1)+a(2)+\dots+a(n)\$ is prime (OEIS A051935)

Background Consider the following sequence (A051935 in OEIS): Start with the term \$2\$. Find the lowest integer \$n\$ greater than \$2\$ such that \$2+n\$ is prime. Find the lowest integer \$n'\$ ...
17
votes
22answers
2k views

Sort by what the digit pairs describe

Given a positive integer, we can form a new number that's described by its digits taken pairwise (with a leading 0 added for numbers with odd number of digits). For eg.: 1234 can be read as one 2, ...
30
votes
18answers
2k views

Custom Number Base Converter

The powers that be want to be able to quickly convert any number they have into their own number base using any format they would like. Input Your program must accept 3 parameters. Number: The ...
8
votes
12answers
311 views

Construct a line graph / conjugate graph

Introduction Given an undirected graph G, we can construct a graph L(G) (called the line graph or conjugate graph) that represents the connections between edges in G. This is done by creating a new ...
22
votes
18answers
1k views

RTA (Reverse-Then-Add) root of a number

The reverse-then-add (RTA) sequence is a sequence obtained by adding a number to its reverse, and repeating the process on the result. For eg., $$ 5 + 5 = 10 \Rightarrow 10 + 01 = 11 \Rightarrow 11 +...
-3
votes
1answer
133 views

number decomposition [duplicate]

It's been a while since I posted here, so here we go another day another challenge. Challenge : Given a number(n) split it into it's prime factors. Input : A ...
0
votes
1answer
118 views

Symmetric Numbers [duplicate]

write a function to tell if a number is symmetric or not. for example: input: 151 output: True input: 142 output: False and so on: 1111 True, 2390 False, 1226221 True
17
votes
34answers
958 views

Calculate power series result [duplicate]

Related: Calculate Power Series Coefficients Given a positive integer \$X\$ and a max exponent (Also a positive integer too) \$N\$ calculate the result of a power series. Example: $$X^0+X^1+X^2+\...
18
votes
29answers
2k views

Count the lucky tickets within the given range

In Russia we have something like a tradition: we like to look for lucky tickets. Here's what a regular ticket looks like: As you can see, the ticket has a six-digit number. A six-digit number is ...
22
votes
16answers
3k views

Find the inverse of a 3 by 3 matrix

Challenge Given nine numbers, a, b, c, d, e, f, g, h, i, as input which correspond to the square matrix: $$\mathbf{M} = \begin{pmatrix}a& b& c\\ d& e&...
15
votes
16answers
1k views

Exact Partial Sum of Harmonic Series

Challenge Given a positive integer N, output the sum of the first N reciprocals as an exact fraction, which is represented as a ...
6
votes
11answers
813 views

Draw a times table (also called modular multiplication circle) of a number \$n\$ with \$k\$ vertices

Not to be confused with this question. You need to draw a times table (also known as Cremona's method for cardioid generation) as shown in this video. The number \$n\$ and \$k\$ will be the inputs. ...
21
votes
2answers
482 views

Existential Golf

Math has a lot of symbols. Some might say too many symbols. So lets do some math with pictures. Lets have a paper, which we will draw on. To start the paper is empty, we will say that is ...
-5
votes
15answers
334 views

Perfect Squares below \$n\$

A perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. Calculate the number of perfect squares below a number \$n\$ where \$...
12
votes
39answers
4k views

Last digit large number

For a given list of number \$[x_1, x_2, x_3, ..., x_n]\$ find the last digit of \$x_1 ^{x_2 ^ {x_3 ^ {\dots ^ {x_n}}}}\$ Example: ...