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 A206954 #7 Jul 22 2025 19:50:04 %S A206954 191,36481,4107593,449797912,50967712088,5791955969105, %T A206954 656572043220119,74406813170700252,8434111346519119622, %U A206954 956049555928840322174,108370550020434256409997,12284018358115973071831348 %N A206954 Number of nX5 0..2 arrays avoiding the pattern z z+1 z in any row, column or nw-to-se diagonal. %C A206954 Column 5 of A206957 %H A206954 R. H. Hardin, <a href="/A206954/b206954.txt">Table of n, a(n) for n = 1..210</a> %e A206954 Some solutions for n=4 %e A206954 ..2..1..0..2..2....1..2..2..1..2....1..0..0..0..0....0..2..2..0..0 %e A206954 ..0..0..2..1..0....0..1..1..2..2....1..2..2..0..0....1..0..1..1..2 %e A206954 ..1..2..0..2..1....1..0..1..2..0....2..0..0..2..1....2..2..1..2..2 %e A206954 ..2..2..2..0..2....1..1..2..0..2....2..1..1..1..1....2..1..2..2..2 %K A206954 nonn %O A206954 1,1 %A A206954 _R. H. Hardin_ Feb 13 2012