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

Author

Jason Kimberley, Apr 02 2012

Keywords

• nonn
• more
• hard

Links

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

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).

Formula

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