Linked Questions
12 questions linked to/from One OEIS after another
54
votes
147
answers
8k
views
The vanilla factorial challenge
Task
Given a non-negative integer \$n\$, evaluate the factorial \$n!\$.
The factorial is defined as follows:
$$
n!=\begin{cases}1 & n=0\\n\times(n-1)!&n>0\end{cases}
$$
Rules
All default I/...
- 73.8k
29
votes
31
answers
3k
views
Deranged !Combinatorics: Compute the Subfactorial
The subfactorial or rencontres numbers (A000166) are a sequence of numbers similar to the factorial numbers which show up in the combinatorics of permutations. In particular the nth subfactorial !n ...
- 196k
14
votes
29
answers
6k
views
RLE Brainfuck dialect
RLE Brainfuck
(related to BF-RLE)
The hypothetical RLE (Run-Length Encoding) dialect of Brainfuck accepts the symbols for the 8 commands and also accepts digits. The digits are used to represent the ...
- 21k
33
votes
21
answers
6k
views
Levi-Civita symbol
The three-dimensional Levi-Civita symbol is a function f taking triples of numbers (i,j,k) each in ...
- 144k
19
votes
21
answers
2k
views
How many partitions do I have?
The partition number of a positive integer is defined as the number of ways it can be expressed as a sum of positive integers. In other words, the number of integer partitions it has. For example, the ...
user70974
25
votes
11
answers
4k
views
Generate a Kolakoski sequence [duplicate]
Definition1
A Kolakoski sequence is a self-describing infinite sequence {kn} of alternating blocks of 1's and 2's, given by the following rules:
k0 = 1
kn = the length of the (n+1)'th ...
- 2,329
12
votes
21
answers
1k
views
An OEIS polyglot
This is an answer-chaining challenge relating to the OEIS.
Oh, the justification for this is because a company needs one program to print out their OEIS sequences real bad and they have every ...
- 3,831
11
votes
12
answers
811
views
Travel Back in Quine
The challenge here is simple, and not at all about byte-count. Your job is to output the first 50 characters of the previous quine's source code, concatenated with the first 50 characters of yours ...
- 20.6k
16
votes
4
answers
846
views
Number of \$n\$-carbon alkanes
Given a positive number \$n\$, find the number of alkanes with \$n\$ carbon atoms, ignoring stereoisomers; or equivalently, the number of unlabeled trees with \$n\$ nodes, such that every node has ...
- 46.5k
11
votes
6
answers
2k
views
Calculate the Kronecker symbol
Relevant links here and here, but here is the short version:
You have an input of two integers \$a\$ and \$b\$ between negative infinity and infinity (though if necessary, I can restrict the range, ...
- 12.2k
14
votes
2
answers
884
views
Counting generalized polyominoes
This challenge will have you count pseudo-polyforms on the snub square tiling.
I think that this sequence does not yet exist on the OEIS, so this challenge exists to compute as many terms as possible ...
- 8,659
-2
votes
4
answers
791
views
Find the hardest OEIS sequence to golf!
Notice: This question originally had people write comments with a shorter program, rather than new answers. This has been changed so that people with shorter programs can get reputation too. Hopefully ...
- 3,129