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 A301955 #4 Mar 29 2018 12:48:51 %S A301955 0,89,1411,56710,1608681,58609226,1969215107,67333850084, %T A301955 2287773842566,77959998302605,2653916633152707,90371628086108933, %U A301955 3077076307444521060,104774663297551634379,3567555401986729558326,121474804497455764013977 %N A301955 Number of 6Xn 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301955 Row 6 of A301951. %H A301955 R. H. Hardin, <a href="/A301955/b301955.txt">Table of n, a(n) for n = 1..210</a> %e A301955 Some solutions for n=5 %e A301955 ..0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0. .0..0..0..0..0 %e A301955 ..0..1..0..0..0. .0..0..0..1..1. .0..1..0..0..0. .0..1..0..1..1 %e A301955 ..1..1..1..0..1. .1..1..1..1..1. .1..1..1..1..0. .1..0..0..0..1 %e A301955 ..1..0..1..1..1. .0..0..0..1..1. .0..0..0..0..0. .1..1..1..1..1 %e A301955 ..0..1..0..1..1. .1..1..0..1..0. .1..1..1..1..0. .0..0..0..1..0 %e A301955 ..0..0..0..1..1. .1..0..0..0..0. .1..1..1..0..0. .1..1..0..0..0 %Y A301955 Cf. A301951. %K A301955 nonn %O A301955 1,2 %A A301955 _R. H. Hardin_, Mar 29 2018