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 A232070 #7 Oct 03 2018 06:19:18 %S A232070 15,87,602,3985,26713,178484,1193537,7979619,53352090,356709629, %T A232070 2384952501,15945724308,106612681357,712809462455,4765824578786, %U A232070 31864172723641,213042987115297,1424399583243252,9523496644232169 %N A232070 Number of (n+1) X (2+1) 0..1 arrays with every element equal to some horizontal, diagonal or antidiagonal neighbor, with top left element zero. %H A232070 R. H. Hardin, <a href="/A232070/b232070.txt">Table of n, a(n) for n = 1..210</a> %F A232070 Empirical: a(n) = 5*a(n-1) + 11*a(n-2) + 2*a(n-3) - 8*a(n-5). %F A232070 Empirical g.f.: x*(15 + 12*x + 2*x^2 - 12*x^3 - 8*x^4) / (1 - 5*x - 11*x^2 - 2*x^3 + 8*x^5). - _Colin Barker_, Oct 03 2018 %e A232070 Some solutions for n=6: %e A232070 ..0..0..0....0..1..0....0..1..0....0..0..0....0..1..0....0..0..0....0..0..0 %e A232070 ..1..1..0....1..0..0....0..0..1....1..1..0....0..0..1....0..1..0....1..0..0 %e A232070 ..0..1..1....0..0..0....0..1..1....1..0..0....0..0..0....1..0..0....1..1..1 %e A232070 ..1..0..1....0..0..0....1..0..1....1..1..1....1..1..0....0..1..0....0..0..0 %e A232070 ..0..1..0....0..1..0....1..0..0....1..1..1....0..0..0....1..1..1....1..0..1 %e A232070 ..0..1..0....1..0..1....1..1..1....0..0..0....1..0..0....0..0..1....1..1..0 %e A232070 ..1..0..1....1..1..0....0..0..0....0..0..0....0..1..1....0..1..0....1..1..1 %Y A232070 Column 2 of A232076. %K A232070 nonn %O A232070 1,1 %A A232070 _R. H. Hardin_, Nov 17 2013