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A143660 Erroneous version of A170946. 0
2, 15, 20, 107 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The theory of dessins d'enfants was initiated by A. Grothendieck. "In this work, using the matrix model approach... we listed all the dessins d'enfants with no more than 4 edges. There are two 1-edge dessins, both of them are of genus zero, fifteen 2-edge dessins, among them only one is of genus 1, twenty 3-edge dessins: 14 sperical [sic] and 6 of genus 1 and one hundred seven 4-edge dessins: 57 spherical dessins, 46 dessins of genus 1 and 4 dessins of genus 2. The total number of dessins is 134."

Note: The fifteen for n=2 is a typo, it should be 5. The sum: 2+5+20+107=134 adds up if we replace fifteen by 5, and moreover, the section on 2-edge dessins lists all 5 (not fifteen) dessins. The correct version of this sequence is given by A170946. - Mark van Hoeij, Jan 23 2011

LINKS

Table of n, a(n) for n=1..4.

N. M. Adrianov, N. Ya. Amburg, V. A. Dremov, Yu. A. Levitskaya, E. M. Kreines, Yu. Yu. Kochetkov, V. F. Nasretdinova and G. B. Shabat, Catalog of dessins d'enfants with <= 4 edges, arXiv:0710.2658 [math.AG], 2007.

CROSSREFS

Sequence in context: A091791 A281660 A244324 * A198391 A278889 A075722

Adjacent sequences:  A143657 A143658 A143659 * A143661 A143662 A143663

KEYWORD

dead

STATUS

approved

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Last modified May 28 15:55 EDT 2020. Contains 334684 sequences. (Running on oeis4.)