A198318 Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 8.

0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 3, 4, 4, 6, 5, 7, 7, 10, 10, 15, 13, 29, 17, 176, 23, 4364, 30, 266398, 39, 20807734, 51

Offset: 0

Author

Jason Kimberley, Dec 19 2012

Keywords

• nonn
• more
• hard

Links

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

Crossrefs

Not necessarily connected regular simple graphs girth exactly g: A198313 (g=3), A198314 (g=4), A198315 (g=5), A198316 (g=6), A198317 (g=7), this sequence (g=8).

Formula

a(n) = A186748(n) + A210718(n).

a(n) = A185318(n) - A185319(n).