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 A297648 #6 May 03 2020 15:34:45 %S A297648 1,10,231,11024,2525244,1906300826,3863740405975,26223048303944542, %T A297648 618905182069042142432,45235515405863464673598537 %N A297648 Number of n X n 0..1 arrays with every 1 horizontally, diagonally or antidiagonally adjacent to 1, 2 or 3 neighboring 1's. %C A297648 Diagonal of A297654. %e A297648 Some solutions for n=4 %e A297648 ..1..1..1..0. .0..1..0..1. .1..0..1..0. .0..1..1..0. .1..1..1..1 %e A297648 ..1..0..0..0. .1..0..1..1. .0..1..0..1. .1..0..0..0. .1..0..0..0 %e A297648 ..0..0..1..0. .0..0..1..0. .1..1..0..0. .0..0..1..0. .0..1..1..0 %e A297648 ..0..0..0..1. .1..1..0..1. .0..1..0..0. .0..0..1..1. .1..1..0..1 %Y A297648 Cf. A297654. %K A297648 nonn %O A297648 1,2 %A A297648 _R. H. Hardin_, Jan 02 2018