A268567 Arises in counting maps on a surface: see Coquereaux-Zuber (2015) for precise definition.

1, 4, 42, 780, 21552, 803760, 38054160, 2194345440, 149604053760, 11794431720960

Offset

1,2

Links

Table of n, a(n) for n=1..10.

R. Coquereaux, J.-B. Zuber, Maps, immersions and permutations, arXiv preprint arXiv:1507.03163, 2015. Also J. Knot Theory Ramifications 25, 1650047 (2016), DOI: http://dx.doi.org/10.1142/S0218216516500474

Crossrefs

Sequence in context: A140055 A221096 A179499 * A197866 A197948 A196194

Adjacent sequences: A268564 A268565 A268566 * A268568 A268569 A268570

Keyword

nonn,more

Author

N. J. A. Sloane, Mar 03 2016

Status

approved