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 A283578 #4 Mar 11 2017 08:23:00 %S A283578 0,3232,194173,4441052,164714523,4558585174,129997769458, %T A283578 3650965394740,99090078168196,2687260014584534,71764403257467215, %U A283578 1902366721060350320,50085438054862185785,1310060351650654162702,34098186251976982332364 %N A283578 Number of 7Xn 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly one element. %C A283578 Row 7 of A283572. %H A283578 R. H. Hardin, <a href="/A283578/b283578.txt">Table of n, a(n) for n = 1..210</a> %e A283578 Some solutions for n=3 %e A283578 ..0..1..0. .0..0..1. .0..1..0. .0..0..1. .0..1..0. .0..0..0. .0..0..0 %e A283578 ..1..0..1. .0..0..1. .1..0..1. .1..0..0. .0..0..0. .1..0..1. .0..0..0 %e A283578 ..0..0..1. .1..0..1. .0..0..1. .0..0..1. .1..0..1. .1..0..1. .1..0..0 %e A283578 ..0..0..0. .0..1..1. .1..0..1. .0..0..1. .0..0..0. .0..1..0. .0..1..1 %e A283578 ..0..1..1. .0..0..1. .0..0..1. .0..1..0. .0..0..0. .0..1..0. .1..0..1 %e A283578 ..0..0..0. .1..0..0. .1..0..0. .1..0..1. .1..1..1. .0..0..1. .1..0..1 %e A283578 ..0..1..0. .0..0..0. .0..0..0. .0..0..1. .1..0..1. .1..0..1. .1..0..1 %Y A283578 Cf. A283572. %K A283578 nonn %O A283578 1,2 %A A283578 _R. H. Hardin_, Mar 11 2017