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

Author

Jason Kimberley, Dec 20 2012

Keywords

• nonn
• more
• hard
• bref

Links

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

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).

Formula

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