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 A302880 #4 Apr 15 2018 10:36:28 %S A302880 16,21,82,285,1197,7580,41498,224087,1300510,7961144,47528608, %T A302880 279333761,1677401880,10223444297,61648514855,368974094762, %U A302880 2225242688063,13491965168663,81443512904106,490081514479072,2957619899837635 %N A302880 Number of 5Xn 0..1 arrays with every element equal to 0, 1, 3, 4 or 5 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero. %C A302880 Row 5 of A302877. %H A302880 R. H. Hardin, <a href="/A302880/b302880.txt">Table of n, a(n) for n = 1..210</a> %e A302880 Some solutions for n=5 %e A302880 ..0..0..0..0..1. .0..1..0..0..0. .0..1..0..1..0. .0..0..0..1..0 %e A302880 ..0..1..0..0..0. .0..1..0..1..1. .1..1..0..1..0. .0..1..0..1..0 %e A302880 ..0..1..0..0..0. .1..0..0..0..0. .0..1..0..1..0. .1..1..0..1..0 %e A302880 ..0..1..1..0..1. .0..0..0..1..1. .0..0..0..1..0. .1..1..1..1..0 %e A302880 ..0..1..0..1..1. .1..0..0..0..0. .1..1..0..1..0. .0..1..1..0..1 %Y A302880 Cf. A302877. %K A302880 nonn %O A302880 1,1 %A A302880 _R. H. Hardin_, Apr 15 2018