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 A207218 #7 Jul 22 2025 20:08:38 %S A207218 191,36481,4916282,647820815,86510224720,11574609426324, %T A207218 1547869995556777,206971107381598775,27675336707209804335, %U A207218 3700661206901289737538,494840604949963261796095,66168472883795299046655248 %N A207218 Number of nX5 0..2 arrays avoiding the pattern z z+1 z in any row or column. %C A207218 Column 5 of A207221 %H A207218 R. H. Hardin, <a href="/A207218/b207218.txt">Table of n, a(n) for n = 1..210</a> %e A207218 Some solutions for n=4 %e A207218 ..2..0..1..2..2....2..1..0..2..2....0..1..1..2..2....0..0..2..1..2 %e A207218 ..1..1..1..1..2....0..0..2..1..0....2..0..1..2..0....0..1..2..0..2 %e A207218 ..1..2..2..2..0....1..2..0..2..0....1..1..2..2..0....2..1..2..2..0 %e A207218 ..1..0..2..2..1....2..2..2..0..2....1..1..2..2..2....1..2..2..2..1 %K A207218 nonn %O A207218 1,1 %A A207218 _R. H. Hardin_ Feb 16 2012