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 A301613 #4 Mar 24 2018 11:41:18 %S A301613 5,361,12467,421025,14345706,488491106,16632517333,566336198475, %T A301613 19283659583317,656605634861657,22357328417975688,761263743052450453, %U A301613 25920919868772588676,882603544282198427622,30052522164474593294535 %N A301613 Number of nX6 0..1 arrays with every element equal to 1, 2 or 3 horizontally or vertically adjacent elements, with upper left element zero. %C A301613 Column 6 of A301615. %H A301613 R. H. Hardin, <a href="/A301613/b301613.txt">Table of n, a(n) for n = 1..210</a> %e A301613 Some solutions for n=5 %e A301613 ..0..0..1..1..1..0. .0..0..1..1..1..1. .0..0..0..1..1..1. .0..0..0..1..1..0 %e A301613 ..0..0..1..0..0..0. .0..0..1..1..0..0. .0..0..1..1..0..1. .0..0..1..0..0..0 %e A301613 ..0..0..0..1..1..0. .0..0..1..0..1..1. .0..0..1..1..0..1. .0..0..1..1..0..0 %e A301613 ..0..1..1..1..0..1. .0..1..1..0..1..1. .0..1..0..0..1..1. .0..0..1..0..0..1 %e A301613 ..0..0..1..0..0..1. .0..0..1..1..1..1. .0..1..1..0..0..0. .0..0..0..1..1..1 %Y A301613 Cf. A301615. %K A301613 nonn %O A301613 1,1 %A A301613 _R. H. Hardin_, Mar 24 2018