A054960 Number of unlabeled graphs with n nodes and an odd number of edges.

0, 1, 2, 5, 16, 78, 522, 6168, 137316, 6002584, 509498932, 82545585936, 25251015681176, 14527077828617744, 15713242984902154384, 32000507852263778595584, 122967932076766466336249888, 893788862572805850273939095424, 12318904626562502262191503745716384

Offset

1,3

Links

Andrew Howroyd, Table of n, a(n) for n = 1..50

V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.

Formula

a(n) = (A000088(n) - A000171(n))/2.

Mathematica

Table[Total[Table[NumberOfGraphs[n, m], {m, 1, Binomial[n, 2], 2}]], {n, 1, 15}]  (* Geoffrey Critzer, Oct 20 2012 *)

Crossrefs

Cf. A000088, A000171.

Cf. A007869 for graphs with an even number of edges.

Sequence in context: A371829 A263914 A218168 * A004110 A236960 A290609

Adjacent sequences: A054957 A054958 A054959 * A054961 A054962 A054963

Keyword

nonn,easy

Author

N. J. A. Sloane, May 24 2000

Extensions

More terms from Vladeta Jovovic, Jul 19 2000

Terms a(18) and beyond from Andrew Howroyd, Sep 17 2018

Status

approved