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 A181249 #5 Jul 22 2025 08:39:04 %S A181249 64,3105,160697,8191392,419045269,21418970801,1095020802848, %T A181249 55979092539545,2861765993703849,146298965997241152, %U A181249 7479088292930771309,382345515897175884705,19546245848381921238016,999242067236417336040593 %N A181249 Number of nX6 binary matrices with no 2X2 block having four 1's. %C A181249 Column 6 of A181253 %H A181249 R. H. Hardin, <a href="/A181249/b181249.txt">Table of n, a(n) for n=1..200</a> %F A181249 Empirical: a(n)=33*a(n-1)+908*a(n-2)+1687*a(n-3)-37947*a(n-4)-16572*a(n-5)+513993*a(n-6)-663729*a(n-7)-486540*a(n-8)+617409*a(n-9)+191835*a(n-10)-49140*a(n-11) %K A181249 nonn %O A181249 1,1 %A A181249 _R. H. Hardin_ Oct 10 2010