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%I #11 Jan 11 2019 19:22:54
%S 0,4,68,964,12836,165784,2103788,26396416,328621604,4068021916,
%T 50142879128
%N Number of 4-regular maps on the Klein bottle with n vertices and 2n edges.
%H Evgeniy Krasko, Alexander Omelchenko, <a href="https://doi.org/10.1016/j.disc.2018.07.013">Enumeration of r-regular maps on the torus. Part I: Rooted maps on the torus, the projective plane and the Klein bottle. Sensed maps on the torus</a>, Discrete Mathematics (2019) Vol. 342, Issue 2, 584-599. Also <a href="https://arxiv.org/abs/1709.03225">arXiv:1709.03225 [math.CO]</a>. See Th. 2.3 and Table 3.
%K nonn,more
%O 0,2
%A _N. J. A. Sloane_, Jan 11 2019