A210713 Number of disconnected regular simple graphs on n vertices with girth exactly 3.

0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 5, 4, 16, 13, 64, 98, 597, 2064, 22472, 112814, 4799607, 31138903, 4207941575, 115979716284, 13482672620149

Offset

0,9

Links

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

Jason Kimberley, Index of sequences counting disconnected k-regular simple graphs with girth exactly g

Formula

a(n) = A068932(n) - A185214(n).

Crossrefs

This sequence is the row sum sequence of the triangle A210703.

Disconnected k-regular simple graphs with girth exactly 3: this sequence (any k), A210703 (triangle); for fixed k: A185033 (k=3), A185043 (k=4), A185053 (k=5), A185063 (k=6).

Sequence in context: A284686 A349451 A054079 * A283825 A005177 A357123

Adjacent sequences: A210710 A210711 A210712 * A210714 A210715 A210716

Keyword

nonn,more,hard

Author

Jason Kimberley, Apr 02 2012

Status

approved