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 A265454 #4 Dec 09 2015 09:59:14 %S A265454 66,3358,216466,13943772,871209026,52509347006,3073046007824, %T A265454 175659478218938,9853875472731614,544420779803461484, %U A265454 29705625866016751450,1604088383366277766514,85864081342833064010380 %N A265454 Number of nX4 0..n+4-2 arrays with each element differing from its horizontal and vertical neighbors by one or two. %C A265454 Column 4 of A265458. %H A265454 R. H. Hardin, <a href="/A265454/b265454.txt">Table of n, a(n) for n = 1..210</a> %e A265454 Some solutions for n=2 %e A265454 ..1..3..2..4....2..0..1..3....4..2..1..2....3..1..2..1....2..3..2..4 %e A265454 ..2..1..0..2....0..2..3..1....3..4..3..4....4..3..1..3....0..2..4..3 %Y A265454 Cf. A265458. %K A265454 nonn %O A265454 1,1 %A A265454 _R. H. Hardin_, Dec 09 2015