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 A228503 #9 Sep 01 2013 17:49:31 %S A228503 5,11,88,358,2002,9528,49101,243118,1228036,6141239,30865981, %T A228503 154742849,776765183,3896668986,19553995645,98108834263,492283814664, %U A228503 2470048647138,12393793010466,62186850336292,312029099308093,1565635002686314 %N A228503 Number of nX5 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally. %C A228503 Column 5 of A228506 %H A228503 R. H. Hardin, <a href="/A228503/b228503.txt">Table of n, a(n) for n = 1..210</a> %F A228503 Empirical: a(n) = 2*a(n-1) +16*a(n-2) +a(n-3) -27*a(n-4) +a(n-5) +4*a(n-6). %F A228503 Empirical: g.f. -x*(5+x-14*x^2+x^3+2*x^4) / ( -1+2*x+16*x^2+x^3-27*x^4+x^5+4*x^6 ). - _R. J. Mathar_, Aug 25 2013 %e A228503 Some solutions for n=4 %e A228503 ..1..0..0..0..0....1..0..0..0..0....1..0..0..0..0....1..0..0..0..1 %e A228503 ..0..0..0..1..0....0..0..1..0..1....0..0..0..0..0....0..0..0..0..0 %e A228503 ..0..0..0..0..0....1..0..0..0..0....0..1..0..0..1....1..0..0..0..0 %e A228503 ..0..0..0..0..1....0..0..0..1..0....0..0..0..0..0....0..0..0..0..0 %K A228503 nonn %O A228503 1,1 %A A228503 _R. H. Hardin_ Aug 23 2013