A006439 Number of tree-rooted toroidal maps with 2 faces and n vertices and without separating loops. (Formerly M3719)

4, 152, 2630, 31500, 303534, 2530976, 19030428, 132386340, 866782510, 5405853200

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..10.

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

Cf. A006440.

Sequence in context: A361774 A294826 A247115 * A264711 A279325 A158104

Adjacent sequences: A006436 A006437 A006438 * A006440 A006441 A006442

Keyword

nonn,more

Author

N. J. A. Sloane

Extensions

Name clarified by Andrew Howroyd, Apr 04 2021

Status

approved