A006903 Number of triangle-free trivalent (or cubic) graphs with 2n labeled nodes. (Formerly M4763)

1, 0, 0, 10, 3360, 1829520, 2010023400, 3622767548400, 9820308795897600, 38117776055769009600, 204209112522362230483200, 1465227517158776390187168000, 13730711637579303579659695248000

Offset

0,4

References

R. W. Robinson, Numerical implementation of graph counting algorithms, AGRC Grant, Math. Dept., Univ. Newcastle, Australia, 1977.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

N. C. Wormald, The number of labeled cubic graphs with no triangles, Congress. Numerantium, 33 (1981), 359-378.

Links

Table of n, a(n) for n=0..12.

Crossrefs

Cf. A014371.

Sequence in context: A001329 A007101 A007103 * A115481 A154238 A234144

Adjacent sequences: A006900 A006901 A006902 * A006904 A006905 A006906

Keyword

nonn,nice

Author

Simon Plouffe and N. J. A. Sloane

Extensions

Confirmed by Gordon F. Royle, May 31 2000

a(0) changed to 1 and a(11)-a(12) added by Sean A. Irvine, Aug 29 2017

Status

approved