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 A239982 #6 Jun 02 2025 09:35:56 %S A239982 1,5,22,171,1391,9079,70107,514297,3533132,27478686,195617485, %T A239982 1396299371,10574699363,74869696354,547239827048,4060652644276, %U A239982 28932235350938,213204213265435,1560042805514282,11221251973358733,82689323867874597 %N A239982 Number of nX4 0..3 arrays with no element equal to zero plus the sum of elements to its left or two plus the sum of elements above it or one plus the sum of the elements diagonally to its northwest, modulo 4. %C A239982 Column 4 of A239986 %H A239982 R. H. Hardin, <a href="/A239982/b239982.txt">Table of n, a(n) for n = 1..210</a> %e A239982 Some solutions for n=4 %e A239982 ..3..0..0..0....3..0..0..0....3..0..0..0....3..0..0..0....3..0..0..0 %e A239982 ..2..3..0..0....2..1..0..0....3..1..3..0....2..1..0..0....3..1..3..0 %e A239982 ..2..0..0..0....2..0..0..0....3..2..3..1....2..0..3..3....3..2..0..3 %e A239982 ..3..0..0..1....3..2..0..3....2..3..3..1....3..0..0..2....2..3..0..2 %K A239982 nonn %O A239982 1,2 %A A239982 _R. H. Hardin_, Mar 30 2014