This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A229931 #6 Jun 02 2025 08:40:00 %S A229931 15,4679,575757,78416265,10521395805,1411363459757,189537122520529, %T A229931 25452175156264451,3417529000078202173,458884977133199962799, %U A229931 61616812650798586337473,8273590477515811155826013 %N A229931 Number of nX5 0..2 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value 2-x(i,j). %C A229931 Column 5 of A229934 %H A229931 R. H. Hardin, <a href="/A229931/b229931.txt">Table of n, a(n) for n = 1..210</a> %e A229931 Some solutions for n=3 %e A229931 ..0..1..1..2..2....0..2..1..1..2....0..2..2..0..2....0..0..2..2..0 %e A229931 ..2..2..0..1..0....0..1..0..0..2....0..0..1..2..1....2..0..2..2..0 %e A229931 ..2..0..1..2..2....1..1..2..0..0....2..2..1..1..1....0..1..1..0..2 %K A229931 nonn %O A229931 1,1 %A A229931 _R. H. Hardin_, Oct 04 2013