A185316 Number of, not necessarily connected, regular simple graphs on n vertices with girth at least 6.

1, 1, 2, 1, 2, 1, 3, 2, 3, 2, 3, 2, 4, 3, 6, 4, 7, 5, 13, 7, 42, 10, 398, 13, 7592, 18, 181251, 25, 4624534, 33, 122090591, 45, 3328930034, 61, 93990693977, 106

Offset: 0

Author

Jason Kimberley, Dec 12 2012

Keywords

• nonn
• more
• hard

Links

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

Crossrefs

Not necessarily connected regular simple graphs with girth at least g: A005176 (g=3), A185314 (g=4), A185315 (g=5), this sequence (g=6), A185317 (g=7), A185318 (g=8), A185319 (g=9).

Formula

a(n) = A186726(n) + A185216(n).