A185163 Number of not necessarily connected 6-regular simple graphs on n vertices with girth exactly 3.

0, 0, 0, 0, 0, 0, 0, 1, 1, 4, 21, 266, 7848, 367860, 21609300, 1470293675, 113314233804, 9799685588955

Offset: 0

Author

Jason Kimberley, Mar 21 2012

Keywords

• nonn
• hard
• more

Links

• Jason Kimberley, Index of sequences counting not necessarily connected k-regular simple graphs with girth exactly g

Crossrefs

Not necessarily connected k-regular simple graphs girth exactly 3: A198313 (any k), A185643 (triangle); fixed k: A026796 (k=2), A185133 (k=3), A185143 (k=4), A185153 (k=5), this sequence (k=6).

Formula

a(n) = A165627(n) - A185364(n).

a(n) = A184953(n) + A185053(n).