A348812 a(n) is the number of rooted 6-regular maps on the Klein bottle with n vertices and 2n edges.
42, 3846, 300048, 22171638, 1595739432, 113110095540, 7939173652032, 553477015433958, 38395171272416568, 2653558455501023196
Offset: 1
Links
- Evgeniy Krasko and Alexander Omelchenko, Enumeration of r-regular Maps on the Torus. Part I: Enumeration of Rooted and Sensed Maps, arXiv:1709.03225 [math.CO], 2017. See also Disc. Math. (2019) Vol. 342, Issue 2, 584-599. Table 3.