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 A298913 #6 Jun 15 2020 13:59:53 %S A298913 1,1,1,3,7,14,40,168,873,5632,63538,1026354,20200595,622554839, %T A298913 29122695476,1747360635695,149225079090933 %N A298913 Number of n X n 0..1 arrays with every element equal to 0, 3, 5, 7 or 8 king-move adjacent elements, with upper left element zero. %C A298913 Diagonal of A298917. %e A298913 Some solutions for n=5 %e A298913 ..0..1..0..1..0. .0..0..0..1..1. .0..0..0..0..0. .0..0..1..1..1 %e A298913 ..1..1..1..1..1. .0..0..0..1..1. .0..0..0..0..0. .0..0..1..1..1 %e A298913 ..0..1..1..1..0. .0..0..0..1..1. .1..1..1..1..1. .0..0..1..1..1 %e A298913 ..1..1..1..1..1. .0..0..0..1..1. .1..1..1..1..1. .0..0..1..1..1 %e A298913 ..0..1..0..1..0. .0..0..0..1..1. .1..1..1..1..1. .0..0..1..1..1 %Y A298913 Cf. A298917. %K A298913 nonn %O A298913 1,4 %A A298913 _R. H. Hardin_, Jan 29 2018