A137858 Number of unlabeled graphs with n nodes and an even sum of nodes and edges.

0, 1, 2, 6, 16, 78, 522, 6178, 137316, 6002584, 509498932, 82545586656, 25251015681176, 14527077828617744, 15713242984902154384, 32000507852263779299344, 122967932076766466336249888

Offset

1,3

Comments

a(n) = A054960(n) for odd n and A007869(n) for even n.

Links

Table of n, a(n) for n=1..17.

Crossrefs

Cf. A054960 Number of unlabeled graphs with n nodes and an odd number of edges. A007869 Complementary pairs of graphs on n nodes. Also unlabeled graphs with n nodes and an even number of edges.

Sequence in context: A147897 A147889 A345246 * A074740 A374826 A204436

Adjacent sequences: A137855 A137856 A137857 * A137859 A137860 A137861

Keyword

nonn

Author

Tanya Khovanova, Apr 29 2008

Status

approved