A210709 Number of trivalent connected simple graphs with 2n nodes and girth at least 9.

1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 18

Offset

0,30

Links

Table of n, a(n) for n=0..29.

Jason Kimberley, Index of sequences counting connected k-regular simple graphs with girth at least g

Formula

a(29) = a(A000066(9)/2) = A052453(9) = 18 is the number of (3,9) cages.

Crossrefs

Trivalent simple graphs with girth at least g: A185131 (triangle); chosen g: A002851 (g=3), A014371 (g=4), A014372 (g=5), A014374 (g=6), A014375 (g=7), A014376 (g=8), this sequence (g=9).

Trivalent simple graphs with girth exactly g: A198303 (triangle); chosen g: A006923 (g=3), A006924 (g=4), A006925 (g=5), A006926 (g=6), A006927 (g=7).

Sequence in context: A128398 A257377 A246649 * A187567 A160145 A072839

Adjacent sequences: A210706 A210707 A210708 * A210710 A210711 A210712

Keyword

nonn,more,hard,bref

Author

Jason Kimberley, Dec 20 2012

Status

approved