

A068932


Number of disconnected regular graphs with n nodes.


19



0, 0, 1, 1, 2, 1, 3, 2, 5, 4, 9, 7, 23, 18, 74, 106, 619, 2076, 22526, 112834, 4799825, 31138965, 4207943011, 115979718015, 13482672647959
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OFFSET

0,5


COMMENTS

A graph is called regular if every node has the same number of edges.
Row sums of A068933.


LINKS

Table of n, a(n) for n=0..24.


FORMULA

a(n) = A005176(n)  A005177(n).


CROSSREFS

Cf. A005176, A005177, A068933.
Sequence in context: A034392 A181531 A034393 * A151533 A128100 A035579
Adjacent sequences: A068929 A068930 A068931 * A068933 A068934 A068935


KEYWORD

hard,more,nonn


AUTHOR

David Wasserman, Mar 08 2002


EXTENSIONS

a(22) corrected and a(23) appended Sep 28 2009, a(24) appended Nov 24 2009, by Jason Kimberley.
a(0)=0 (due to the empty graph being vacuously connected) inserted by Jason Kimberley, Apr 11 2012


STATUS

approved



