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 A303618 #6 Sep 16 2020 19:06:21 %S A303618 1,2,38,325,37910,6446485,6323564388,18955122420980,214926958781186214 %N A303618 Number of n X n 0..1 arrays with every element equal to 0, 2, 3, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A303618 Diagonal of A303624. %e A303618 Some solutions for n=5 %e A303618 ..0..0..1..1..0. .0..0..0..0..0. .0..0..0..1..1. .0..1..1..1..0 %e A303618 ..0..0..0..1..1. .0..0..1..0..0. .0..0..1..1..1. .1..1..0..1..1 %e A303618 ..1..0..0..0..1. .1..0..1..0..0. .1..0..1..1..1. .1..1..1..1..0 %e A303618 ..0..0..0..1..1. .0..0..0..0..0. .0..0..1..1..1. .0..0..0..1..1 %e A303618 ..0..0..1..1..0. .0..0..1..0..1. .0..0..0..1..0. .1..0..1..1..1 %Y A303618 Cf. A303624. %K A303618 nonn %O A303618 1,2 %A A303618 _R. H. Hardin_, Apr 27 2018