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 A301847 #4 Mar 27 2018 14:36:20 %S A301847 64,8192,132971,3518619,77396422,1812097252,41966406867,972282892539, %T A301847 22595595313115,524762543383531,12194289128927894,283431884166143510, %U A301847 6588576515306179215,153173958754721101279,3561231247509661888958 %N A301847 Number of 7Xn 0..1 arrays with every element equal to 0, 1 or 2 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301847 Row 7 of A301841. %H A301847 R. H. Hardin, <a href="/A301847/b301847.txt">Table of n, a(n) for n = 1..210</a> %e A301847 Some solutions for n=5 %e A301847 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A301847 ..1..1..1..0..0. .1..1..1..0..0. .1..1..1..0..0. .1..1..1..0..0 %e A301847 ..0..0..1..0..0. .0..0..1..0..0. .0..0..1..1..0. .0..0..1..1..0 %e A301847 ..0..0..1..1..0. .0..0..1..1..0. .0..0..1..0..0. .0..0..0..0..1 %e A301847 ..0..0..0..1..1. .0..0..0..1..0. .1..0..1..1..1. .1..1..1..0..0 %e A301847 ..1..1..0..0..0. .1..0..1..0..1. .0..0..0..0..1. .0..0..1..1..0 %e A301847 ..1..0..1..1..0. .0..1..1..1..0. .1..1..0..0..1. .0..0..1..1..1 %Y A301847 Cf. A301841. %K A301847 nonn %O A301847 1,1 %A A301847 _R. H. Hardin_, Mar 27 2018