A140440 Number of n-node biconnected graphs with girth at least 5.

0, 0, 0, 0, 1, 1, 2, 5, 12, 40, 154, 766, 4672, 34547, 302185, 3073267, 35933851, 479768761, 7284446498, 125435333136

Offset

1,7

Links

Table of n, a(n) for n=1..20.

Example

The 5 graphs of order 8 are:
0: 4 6; 1: 5 6; 2: 5 7; 3: 6 7; 4: 0 7; 5: 1 2; 6: 0 1 3; 7: 2 3 4;
0: 4 5; 1: 4 6; 2: 5 7; 3: 6 7; 4: 0 1; 5: 0 2; 6: 1 3; 7: 2 3;
0: 4 5; 1: 4 6; 2: 5 7; 3: 6 7; 4: 0 1 7; 5: 0 2; 6: 1 3; 7: 2 3 4;
0: 4 5; 1: 4 7; 2: 5 6; 3: 6 7; 4: 0 1 6; 5: 0 2 7; 6: 2 3 4; 7: 1 3 5;
0: 3 6; 1: 4 6; 2: 5 6; 3: 0 7; 4: 1 7; 5: 2 7; 6: 0 1 2; 7: 3 4 5.

Crossrefs

Cf. A126757.

Sequence in context: A051436 A054581 A203151 * A005664 A364761 A009739

Adjacent sequences: A140437 A140438 A140439 * A140441 A140442 A140443

Keyword

nonn,more

Author

Brendan McKay, Jun 17 2008

Extensions

a(18)-a(20) from Brendan McKay, Jun 13 2021

Status

approved