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 A281604 #5 Apr 26 2021 22:01:57 %S A281604 224,6596,302304,15975093,839574485,44428349137,2352459742664, %T A281604 124612725916938,6601564375598261,349739353333596632 %N A281604 Number of n X 7 0..2 arrays with no element equal to more than one of its horizontal, diagonal or antidiagonal neighbors and with new values introduced in order 0 sequentially upwards. %C A281604 Column 7 of A281605. %e A281604 Some solutions for n=2 %e A281604 ..0..1..2..0..2..0..2. .0..0..1..0..2..1..0. .0..1..0..1..2..0..1 %e A281604 ..1..0..2..0..2..1..1. .1..2..1..0..2..1..2. .0..2..2..1..0..2..1 %Y A281604 Cf. A281605. %K A281604 nonn %O A281604 1,1 %A A281604 _R. H. Hardin_, Jan 25 2017