A290819 Number of rooted 4-regular one-face maps on genus g surface.

1, 45, 9450, 4729725, 4341887550, 6352181485650, 13566444744352500, 39834473380605028125, 153946961458244898693750, 757572997336023146471943750, 4625189759553876588251163487500, 34307345041490879593353005168531250, 303883906271359598859584503473567187500, 3168250194798584983481619521143486701562500, 38405528861348447169764191835301345796340625000

Offset

1,2

Links

Table of n, a(n) for n=1..15.

Evgeniy Krasko, Alexander Omelchenko, Enumeration of 4-regular one-face maps, European Journal of Combinatorics, Volume 62, 2017, Pages 167-177.

Formula

a(g) = 2*((4g-2)!)/((4^g)*(g!)*((g-1)!)).

Example

On a torus (g=1) there exists only one 4-regular one-face map.

Crossrefs

Sequence in context: A364172 A209275 A199355 * A163035 A358707 A184136

Adjacent sequences: A290816 A290817 A290818 * A290820 A290821 A290822

Keyword

nonn

Author

Evgeniy Krasko, Sep 03 2017

Status

approved