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 A298655 #6 Jun 15 2020 11:22:42 %S A298655 0,3,15,40,177,1116,7964,89543,1367704,32451809,1028816587 %N A298655 Number of n X n 0..1 arrays with every element equal to 1, 2, 4, 6 or 7 king-move adjacent elements, with upper left element zero. %C A298655 Diagonal of A298660. %e A298655 Some solutions for n=5 %e A298655 ..0..1..0..0..1. .0..0..0..0..0. .0..1..1..1..1. .0..0..0..0..1 %e A298655 ..0..1..1..1..0. .1..1..1..1..1. .0..0..1..1..0. .1..1..1..1..1 %e A298655 ..0..1..1..1..0. .0..0..0..0..0. .1..1..1..1..0. .0..1..1..0..0 %e A298655 ..0..1..0..1..0. .1..1..1..1..1. .1..0..0..0..1. .0..1..1..1..1 %e A298655 ..1..0..1..0..1. .0..0..0..0..0. .0..0..0..1..0. .1..1..1..0..0 %Y A298655 Cf. A298660. %K A298655 nonn %O A298655 1,2 %A A298655 _R. H. Hardin_, Jan 24 2018