A361411 Number of cubic graphs on 2n unlabeled vertices rooted at a pair of indistinguishable vertices.
0, 1, 5, 33, 257, 2443, 27682, 363759, 5405697, 89134360, 1609418390, 31525697245, 665263778962, 15039817276939, 362579178545598, 9284375250749758, 251643492565059981, 7197256536139662143, 216621907269166632361, 6844093745422473471562
Offset: 1