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A290819 Number of rooted 4-regular one-face maps on genus g surface. 1
1, 45, 9450, 4729725, 4341887550, 6352181485650, 13566444744352500, 39834473380605028125, 153946961458244898693750, 757572997336023146471943750, 4625189759553876588251163487500, 34307345041490879593353005168531250, 303883906271359598859584503473567187500, 3168250194798584983481619521143486701562500, 38405528861348447169764191835301345796340625000 (list; graph; refs; listen; history; text; internal format)
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: A134229 A209275 A199355 * A163035 A184136 A101994

Adjacent sequences:  A290816 A290817 A290818 * A290820 A290821 A290822

KEYWORD

nonn

AUTHOR

Evgeniy Krasko, Sep 03 2017

STATUS

approved

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Last modified January 22 21:47 EST 2022. Contains 350504 sequences. (Running on oeis4.)