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 A185516 #7 Jul 22 2025 09:51:38 %S A185516 2553,115979,2490449,80761059,2183297449,65652458491,1894624012417, %T A185516 56140705014995,1649002255383641,48754926946880491, %U A185516 1438991178016735921,42542454880958044611,1257346657004360967433,37177308864717054716635 %N A185516 Number of (n+1)X5 0..2 arrays with every 2X2 subblock singular. %C A185516 Column 4 of A185521 %H A185516 R. H. Hardin, <a href="/A185516/b185516.txt">Table of n, a(n) for n = 1..200</a> %F A185516 Empirical: a(n)=61*a(n-1)-1038*a(n-2)-2374*a(n-3)+235515*a(n-4)-2269967*a(n-5)+4091988*a(n-6)+57111048*a(n-7)-371380096*a(n-8)+662678992*a(n-9)+937755776*a(n-10)-4856175360*a(n-11)+5080858624*a(n-12)+506806272*a(n-13)-2361655296*a(n-14) %e A185516 Some solutions for 3X5 %e A185516 ..2..1..2..1..0....0..0..0..2..1....1..0..2..2..2....0..2..1..1..1 %e A185516 ..0..0..0..0..0....1..0..0..0..0....0..0..0..0..0....0..0..0..0..0 %e A185516 ..0..1..0..1..1....0..0..0..1..0....0..0..2..1..2....2..2..1..1..1 %K A185516 nonn %O A185516 1,1 %A A185516 _R. H. Hardin_ Jan 29 2011