A292468 Number of 4-regular maps with n vertices on the torus, up to orientation-preserving and orientation-reversing isomorphisms.

1, 4, 20, 133, 1013, 9209, 89889, 929373, 9880120, 107087360, 1174950951, 13008800489, 145024885270, 1625819872988, 18311555574347, 207068032188985, 2349706730746994, 26745505016101977, 305267158873891108, 3492857897924201864

Offset

1,2

Links

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

E. Krasko and A. Omelchenko, Enumeration of r-regular Maps on the Torus. Part II: Enumeration of Unsensed Maps, arXiv preprint arXiv:1709.03230 [math.CO], 2017. See Table 1, p. 20.

E. Krasko and A. Omelchenko, Enumeration of r-regular maps on the torus. Part II: Unsensed maps, Discrete Mathematics, Volume 342, Issue 2, February 2019, pp. 600-614.

Crossrefs

Cf. A292971 (enumerates up to orientation-preserving isomorphisms only), A292405, A292408.

Sequence in context: A333371 A251179 A201355 * A360660 A143463 A290444

Adjacent sequences: A292465 A292466 A292467 * A292469 A292470 A292471

Keyword

nonn

Author

Evgeniy Krasko, Sep 17 2017

Status

approved