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 A141483 #15 Apr 01 2016 08:58:11 %S A141483 1,2,1,5,2,35,5,314,35,6427,314,202841,6427,12727570,202841, %T A141483 1355115601,12727570,269718819131,1355115601,94707789944544, %U A141483 269718819131,60711713670028729,94707789944544,69645620389200894313 %N A141483 Number of n X n binary matrices, symmetric under horizontal and vertical reflection, with no more than 1 one in any 2 X 2 subblock. %C A141483 a(2n-1) = A063443(n+1). - _Vaclav Kotesovec_, May 01 2012 %C A141483 a(2n) = a(2n-3), for n>1. - _Vaclav Kotesovec_, Apr 01 2016 %H A141483 R. H. Hardin and Vaclav Kotesovec, <a href="/A141483/b141483.txt">Table of n, a(n) for n = 0..78</a> (terms 0..30 from R. H. Hardin, terms 31..78 after A063443) %K A141483 nonn %O A141483 0,2 %A A141483 _R. H. Hardin_, Aug 09 2008