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 A301789 #6 Jun 07 2021 13:13:40 %S A301789 21,35,59,100,171,294,508,881,1532,2670,4661,8147,14254,24957,43721, %T A301789 76625,134335,235566,413157,724732,1271408,2230625,3913758,6867218, %U A301789 12049871,21144385,37103604,65109365,114255101,200498599,351843723 %N A301789 Number of n X 7 0..1 arrays with every element equal to 0 or 1 horizontally or antidiagonally adjacent elements, with upper left element zero. %C A301789 Column 7 of A301790. %H A301789 R. H. Hardin, <a href="/A301789/b301789.txt">Table of n, a(n) for n = 1..210</a> %F A301789 Empirical: a(n) = 2*a(n-1) -a(n-4) -a(n-6). %e A301789 Some solutions for n=5 %e A301789 ..0..1..1..0..1..0..0. .0..0..1..1..0..0..1. .0..1..1..0..0..1..0 %e A301789 ..0..0..1..0..1..1..0. .1..0..0..1..1..0..1. .0..0..1..1..0..1..0 %e A301789 ..1..0..1..0..0..1..1. .1..1..0..0..1..0..0. .1..0..0..1..0..1..0 %e A301789 ..1..0..1..1..0..0..1. .0..1..1..0..1..1..0. .1..1..0..1..0..1..1 %e A301789 ..1..0..0..1..1..0..0. .0..0..1..0..0..1..0. .0..1..0..1..0..0..1 %Y A301789 Cf. A301790. %K A301789 nonn %O A301789 1,1 %A A301789 _R. H. Hardin_, Mar 26 2018