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 A302001 #4 Mar 30 2018 12:31:31 %S A302001 0,13,15,74,468,2036,10982,53440,271596,1360466,6832459,34345485, %T A302001 172485648,866676017,4353899691,21873626234,109891360736,552080909728, %U A302001 2773601514082,13934283247296,70004406947220,351694969884786 %N A302001 Number of 4Xn 0..1 arrays with every element equal to 1, 2 or 4 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A302001 Row 4 of A301999. %H A302001 R. H. Hardin, <a href="/A302001/b302001.txt">Table of n, a(n) for n = 1..210</a> %e A302001 Some solutions for n=5 %e A302001 ..0..0..1..1..0. .0..0..1..1..0. .0..0..1..1..0. .0..0..1..1..0 %e A302001 ..0..0..0..0..0. .1..1..1..0..0. .0..0..1..0..1. .0..0..1..0..0 %e A302001 ..1..1..0..1..1. .1..0..1..1..1. .0..1..0..1..0. .0..1..1..0..1 %e A302001 ..1..1..1..0..0. .0..1..0..0..0. .1..0..1..0..0. .0..0..0..1..1 %Y A302001 Cf. A301999. %K A302001 nonn %O A302001 1,2 %A A302001 _R. H. Hardin_, Mar 30 2018