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 A206953 #7 Jul 22 2025 19:49:57 %S A206953 69,4761,218637,9803278,449797912,20694430627,950821989599, %T A206953 43676385937074,2006497292305518,92180116069921220, %U A206953 4234783426805045787,194547099770290413016,8937559013725835053331,410594472108308448412855 %N A206953 Number of nX4 0..2 arrays avoiding the pattern z z+1 z in any row, column or nw-to-se diagonal. %C A206953 Column 4 of A206957 %H A206953 R. H. Hardin, <a href="/A206953/b206953.txt">Table of n, a(n) for n = 1..210</a> %e A206953 Some solutions for n=4 %e A206953 ..0..2..0..1....0..2..2..2....2..0..0..1....0..2..0..0....2..1..2..2 %e A206953 ..2..0..1..1....1..1..0..2....1..1..0..1....0..1..2..0....2..2..1..2 %e A206953 ..0..2..1..1....2..0..1..1....2..2..1..0....1..2..2..0....0..2..2..2 %e A206953 ..2..0..0..1....2..2..1..2....2..2..2..0....1..2..2..2....0..0..2..1 %K A206953 nonn %O A206953 1,1 %A A206953 _R. H. Hardin_ Feb 13 2012