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 A301787 #9 Apr 03 2018 04:16:24 %S A301787 8,14,25,45,82,150,275,505,928,1706,3137,5769,10610,19514,35891,66013, %T A301787 121416,223318,410745,755477,1389538,2555758,4700771,8646065,15902592, %U A301787 29249426,53798081,98950097,181997602,334745778,615693475,1132436853 %N A301787 Number of nX5 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301787 Column 5 of A301790. %H A301787 R. H. Hardin, <a href="/A301787/b301787.txt">Table of n, a(n) for n = 1..210</a> %F A301787 Empirical: a(n) = 2*a(n-1) -a(n-4). %e A301787 Some solutions for n=5 %e A301787 ..0..0..1..0..1. .0..1..1..0..1. .0..0..1..0..0. .0..1..0..1..0 %e A301787 ..1..0..1..0..1. .0..0..1..0..1. .1..0..1..1..0. .1..0..1..0..1 %e A301787 ..1..0..1..0..1. .1..0..1..0..1. .1..0..0..1..0. .1..0..1..0..1 %e A301787 ..0..1..0..1..0. .1..0..1..0..1. .1..1..0..1..0. .1..0..1..0..1 %e A301787 ..0..1..0..1..0. .1..0..1..0..1. .0..1..0..1..0. .1..0..1..0..0 %Y A301787 Cf. A301790, A164398. %K A301787 nonn %O A301787 1,1 %A A301787 _R. H. Hardin_, Mar 26 2018