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A103869 Number of unlabeled graphs with n nodes whose adjacency matrix has nonzero even determinant. 1
0, 0, 1, 0, 9, 10, 354, 1752, 141494, 3313095 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,5

LINKS

Table of n, a(n) for n=1..10.

FORMULA

a(n) = A140981(n) - A133206(n).

MATHEMATICA

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

CROSSREFS

Cf. A133206, A140981, A141040, A109717, A000088.

Sequence in context: A221201 A119159 A041415 * A041753 A042191 A042729

Adjacent sequences:  A103866 A103867 A103868 * A103870 A103871 A103872

KEYWORD

more,nonn

AUTHOR

Tanya Khovanova, Aug 29 2008

EXTENSIONS

a(8)-a(10) from Andrew Howroyd, Nov 04 2017

STATUS

approved

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Last modified March 19 17:21 EDT 2019. Contains 321330 sequences. (Running on oeis4.)