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 A103869 #12 Feb 21 2024 01:19:29
%S A103869 0,0,1,0,9,10,354,1752,141494,3313095,728952205
%N A103869 Number of unlabeled graphs with n nodes whose adjacency matrix has nonzero even determinant.
%F A103869 a(n) = A140981(n) - A133206(n).
%F A103869 For odd n, a(n) = A109717(n). For even n, a(n) = A109717(n) - A141040(n/2). - _Max Alekseyev_, Feb 20 2024
%t A103869 k = {}; For[i = 1, i < 8, i++, lg = ListGraphs[i] ; len = Length[lg]; k = Append[k, Length[Select[Range[len], Det[ToAdjacencyMatrix[lg[[ # ]]]] != 0 && Mod[Det[ToAdjacencyMatrix[lg[[ # ]]]], 2] == 0 &]]]]; k
%Y A103869 Cf. A133206, A140981, A141040, A109717, A000088.
%K A103869 more,nonn
%O A103869 1,5
%A A103869 _Tanya Khovanova_, Aug 29 2008
%E A103869 a(8)-a(10) from _Andrew Howroyd_, Nov 04 2017
%E A103869 a(11) from A109717 added by _Max Alekseyev_, Feb 20 2024