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 A118996 #8 Jun 17 2025 21:57:37 %S A118996 0,3,27,190,4410,753592,127793708,21893984392,9100020369720, %T A118996 16451259308386616 %N A118996 Number of real n X n symmetric (0,1) matrices with negative determinant. %F A118996 a(n) = A086899(n) - A086900(n) = 2^(n*(n+1)/2) - A086906(n) - A086900(n). - _Max Alekseyev_, Jun 12 2025 %Y A118996 Cf. A086899, A086900, A086906, A118997, A118998, A118999, A119006. %K A118996 nonn,more %O A118996 1,2 %A A118996 _Giovanni Resta_, May 08 2006 %E A118996 a(8)-a(10) from _Max Alekseyev_, Jun 17 2025