# Tag Info

Accepted

### Extending OEIS: Counting Diamond Tilings

Algebra, graph theory, Möbius inversion, research, and Java The symmetry group of the hexagon is the dihedral group of order 12, and is generated by a 60 degree rotation and a mirror flip across a ...

### Absolute Sums of Sidi Polynomial Coefficients

Python 2, 43 bytes f=lambda n,k=1:k/n or n*f(n,k+1)+k*f(n-1,k) Try it online! A different approach Ever since I posted this challenge, I tried to come up with a ...

### Print all colorings of a 3x3 grid

Mathematica, 25 bytes Image/@{0,1}~Tuples~{3,3} Gives an array with all the grids as images, which is also directly displayed on screen: (Cropped so as not to ...

### How many partitions do I have?

Mathematica, 11 bytes PartitionsP Explanation ¯\_(ツ)_/¯

### Anaglot Polygrams

34 Languages, 19 bytes, Score: 38,832,018,459,912,437,760,000 Here is a quick answer I threw together to show that it is possible to get an answer scoring better than 1. ...

### Every word from babab to zyzyz

Mathematica, 72 65 61 bytes Print@@@Tuples@{a=##/(b=#5#9#15#21#25#)&@@Alphabet[],b,a,b,a} For testing, I recommend replacing ...

### Catalan Numbers

C, 78 52 39 34 33 bytes Even more C magic (thanks xsot): c(n){return!n?:(4+6./~n)*c(n-1);} ?: is a GNU extension. This time ...

### Concentric rings on a snub square tiling

Ruby, 26 bytes ->n{~-n*12-496/4**n%4+1/n} Try it online! Revised version adding 1/n and subtracting ...

### Bernoulli Numbers

Mathematica, 40 28 23 22 bytes Using the famous formula n*ζ(1−n)=−Bn, where ζ is the Riemann Zeta function. If[#>0,-Zeta[1-#]#,1]& The same length: <...

### Catalan Numbers

Jelly, 4 bytes Ḥc÷‘ Try it online! How it works ...

### The square root of the square root of the square root of the…

APL (Dyalog Unicode), 39 bytes +/⊢{∨/⍺⍵<⍵0:0⋄⍺=0:1⋄+/∊∇¨/⍺(⍵*2)-⊂⍳⍺}¨⍳ Try it online! A tacit function containing an inner dfn to use recursion. Does not use ...

### Compute the multinomial coefficient

Jelly, 7 6 bytes ;_/!:/ Look ma, no Unicode! This program takes a single list as input, with n at its first index. Try it online! or verify all test cases at ...

Accepted

### Print all colorings of a 3x3 grid

K, 11 bytes (3 3#)'!9#2 Output example: ...