

A198317


Number of, not necessarily connected, regular simple graphs on n vertices with girth exactly 7.


5



0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 3, 4, 4, 7, 5, 27, 7, 553, 10, 30379, 13, 1782854, 18, 95079100, 24, 4686063134, 32
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OFFSET

0,22


LINKS

Table of n, a(n) for n=0..39.
Jason Kimberley, Index of sequences counting not necessarily connected kregular simple graphs with girth exactly g


FORMULA

a(n) = A186747(n) + A210717(n).
a(n) = A185317(n)  A185318(n).


CROSSREFS

Not necessarily connected regular simple graphs girth exactly g: A198313 (g=3), A198314 (g=4), A198315 (g=5), A198316 (g=6), this sequence (g=7), A198318 (g=8).
Sequence in context: A225482 A004056 A284334 * A036822 A056099 A084848
Adjacent sequences: A198314 A198315 A198316 * A198318 A198319 A198320


KEYWORD

nonn,more,hard


AUTHOR

Jason Kimberley, Dec 18 2012


STATUS

approved



