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A185133
Number of not necessarily connected 3-regular simple graphs on 2n vertices with girth exactly 3.
14
0, 0, 1, 1, 4, 15, 71, 428, 3406, 34270, 418621, 5937051, 94782437, 1670327647, 32090011476, 666351752261, 14859579573845
OFFSET
0,5
FORMULA
a(n) = A005638(n) - A185334(n).
a(n) = A006923(n) + A185033(n).
CROSSREFS
Not necessarily connected k-regular simple graphs girth exactly 3: A198313 (any k), A185643 (triangle); fixed k: A026796 (k=2), this sequence (k=3), A185143 (k=4), A185153 (k=5), A185163 (k=6).
Not necessarily connected 3-regular simple graphs on 2n vertices with girth exactly g: A185130 (triangle); fixed g: this sequence (g=3), A185134 (g=4), A185135 (g=5), A185136 (g=6).
Sequence in context: A366034 A027316 A085349 * A278640 A026992 A039764
KEYWORD
nonn,hard,more
AUTHOR
Jason Kimberley, Mar 21 2012
STATUS
approved