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 A268760 #7 Apr 19 2020 23:42:38 %S A268760 0,6,56,1148,32056,1552272,127676872,18045771274,4495138018796, %T A268760 1955829240647962,1511334747222697904,2064152526111916503300, %U A268760 5022957354228609008158500,21748481726801956896608976098 %N A268760 Number of n X n binary arrays with some element plus some horizontally, vertically, diagonally or antidiagonally adjacent neighbor totalling two exactly once. %C A268760 Diagonal of A268766. %H A268760 R. H. Hardin, <a href="/A268760/b268760.txt">Table of n, a(n) for n = 1..26</a> %e A268760 Some solutions for n=4 %e A268760 ..0..0..1..1. .0..0..0..0. .0..1..0..1. .0..0..0..1. .0..0..0..0 %e A268760 ..1..0..0..0. .1..0..0..0. .0..0..0..0. .1..1..0..0. .1..0..0..1 %e A268760 ..0..0..0..1. .0..0..0..1. .1..0..0..0. .0..0..0..1. .1..0..0..0 %e A268760 ..1..0..0..0. .0..1..0..1. .1..0..1..0. .0..1..0..0. .0..0..0..1 %Y A268760 Cf. A268766. %K A268760 nonn %O A268760 1,2 %A A268760 _R. H. Hardin_, Feb 13 2016