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 A185520 #7 Jul 22 2025 09:52:06 %S A185520 841449,853020411,119752453041,56140705014995,12721664424927033, %T A185520 4536327635584899147,1241739109392066416737,401495654334865659721795, %U A185520 118095161592668358071069961,36895636527963491594862394779 %N A185520 Number of (n+1)X9 0..2 arrays with every 2X2 subblock singular. %C A185520 Column 8 of A185521 %H A185520 R. H. Hardin, <a href="/A185520/b185520.txt">Table of n, a(n) for n = 1..72</a> %e A185520 Some solutions for 3X9 %e A185520 ..0..0..0..0..0..0..2..0..0....0..0..0..0..2..0..0..1..1 %e A185520 ..0..0..0..0..0..0..0..0..1....0..0..0..0..0..0..0..0..0 %e A185520 ..0..0..0..0..0..2..0..0..0....0..0..1..0..0..0..1..1..1 %K A185520 nonn %O A185520 1,1 %A A185520 _R. H. Hardin_ Jan 29 2011