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 A181248 #5 Jul 22 2025 08:38:57 %S A181248 32,819,22077,587920,15701273,419045269,11185495872,298561305103, %T A181248 7969215344753,212714316418464,5677773794982333,151551208150533689, %U A181248 4045206823611571168,107974712600136074779,2882062422625926933109 %N A181248 Number of nX5 binary matrices with no 2X2 block having four 1's. %C A181248 Column 5 of A181253 %H A181248 R. H. Hardin, <a href="/A181248/b181248.txt">Table of n, a(n) for n=1..200</a> %F A181248 Empirical: a(n)=20*a(n-1)+188*a(n-2)-192*a(n-3)-1660*a(n-4)+2804*a(n-5)-507*a(n-6)-624*a(n-7) %K A181248 nonn %O A181248 1,1 %A A181248 _R. H. Hardin_ Oct 10 2010