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 A206861 #7 Jul 22 2025 19:44:10 %S A206861 529,279841,61164640,13093461017,3092914364659,729358354663001, %T A206861 169438223533971179,39337025494858264742,9160013752465174862941, %U A206861 2134232035568356911671588,496969525342232065594867876 %N A206861 Number of nX6 0..2 arrays avoiding the pattern z z+1 z in any row, column, diagonal or antidiagonal. %C A206861 Column 6 of A206863 %H A206861 R. H. Hardin, <a href="/A206861/b206861.txt">Table of n, a(n) for n = 1..60</a> %e A206861 Some solutions for n=4 %e A206861 ..2..2..2..1..2..2....2..2..1..0..1..1....2..2..1..2..2..2....0..2..1..2..2..1 %e A206861 ..0..2..2..0..0..2....0..0..2..0..0..0....1..0..0..1..2..2....1..1..2..0..1..2 %e A206861 ..1..0..1..2..0..2....0..1..2..0..0..1....0..1..1..0..2..2....2..1..2..2..1..2 %e A206861 ..1..2..2..2..0..2....0..2..2..2..0..1....1..1..1..1..0..2....2..2..2..2..0..1 %K A206861 nonn %O A206861 1,1 %A A206861 _R. H. Hardin_ Feb 13 2012