A198316 Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 6.

0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 1, 2, 1, 2, 1, 7, 2, 35, 3, 389, 4, 7579, 6, 181233, 9, 4624493, 12, 122090019, 17, 3328899632, 24, 93988911093, 57

Offset

0,15

Links

Table of n, a(n) for n=0..35.

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

Formula

a(n) = A186746(n) + A210716(n).

a(n) = A185316(n) - A185317(n).

Crossrefs

Not necessarily connected regular simple graphs girth exactly g: A198313 (g=3), A198314 (g=4), A198315 (g=5), this sequence (g=6), A198317 (g=7), A198318 (g=8).

Sequence in context: A016543 A300585 A145999 * A011128 A245595 A146003

Adjacent sequences: A198313 A198314 A198315 * A198317 A198318 A198319

Keyword

nonn,more,hard

Author

Jason Kimberley, Dec 13 2012

Status

approved