A006425 - OEIS

A006425

Number of rooted toroidal maps with 2 vertices and n faces and no isthmuses.
(Formerly M3700)

4, 79, 900, 7885, 59080, 398846, 2499096, 14805705, 83969600, 459868530, 2447439384, 12718070274, 64766697520, 324156347260, 1598200903280, 7776728909121, 37404399901296, 178060831286890, 839857764202520, 3928581810398630, 18239060530882224, 84101317494787684

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OFFSET

1,1

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=1..22.

T. R. S. Walsh and A. B. Lehman, Counting rooted maps by genus. III: Nonseparable maps, J. Combinatorial Theory Ser. B 18 (1975), 222-259.

CROSSREFS

A diagonal of A343092.

Sequence in context: A215843 A374523 A048957 * A065930 A018807 A216410

Adjacent sequences: A006422 A006423 A006424 * A006426 A006427 A006428