A361408 Number of connected cubic graphs on 2n unlabeled vertices rooted at a pair of indistinguishable vertices.

0, 1, 5, 31, 248, 2382, 27233, 359800, 5364193, 88622485, 1602171855, 31410476113, 663240471075, 15001046054183, 361775504849332, 9266474332849318, 251217335356943672, 7186461542458525108, 216332059500870350414, 6835872042063656823802

Offset

1,3

Links

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

Formula

G.f.: B(x)/C(x) - (D(x) + D(x^2))/2 where B(x), C(x) and D(x) are the g.f.s of A361411, A005638 and A361407, respectively.

Crossrefs

Column k=2 of A321304.

Cf. A002851, A005638, A361407, A361411.

Sequence in context: A276312 A024451 A046852 * A056541 A291885 A126121

Adjacent sequences: A361405 A361406 A361407 * A361409 A361410 A361411

Keyword

nonn

Author

Andrew Howroyd, Mar 11 2023

Status

approved