login
This site is supported by donations to The OEIS Foundation.
Logo

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A137861 Number of unlabeled graphs with n nodes and an odd sum of nodes and edges. 0
1, 1, 2, 5, 18, 78, 522, 6168, 137352, 6002584, 509498932, 82545585936, 25251015686776, 14527077828617744, 15713242984902154384, 32000507852263778595584, 122967932076766466347469888 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

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

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: A189281 A006848 A206293 * A192637 A111916 A118187

Adjacent sequences:  A137858 A137859 A137860 * A137862 A137863 A137864

KEYWORD

nonn

AUTHOR

Tanya Khovanova (tanyakh(AT)yahoo.com), Apr 29 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified February 15 03:33 EST 2012. Contains 205694 sequences.