A060348 a(n) = n^n * (n^2 - 1)/24.

9, 160, 3125, 68040, 1647086, 44040192, 1291401630, 41250000000, 1426558353055, 53125098504192, 2120125746145771, 90285055457658880, 4087009643554687500, 195996655783163985920, 9926883142636041170124, 529537075346699234869248

Offset

3,1

Comments

For n >= 3, a(n) is the number of nonequivalent primitive meromorphic functions with one pole of order n on a Riemann surface of genus 1.

References

B. Shapiro, M. Shapiro and A. Vainshtein, Ramified coverings of S^2 with one degenerate branching point and enumeration of edge-ordered graphs, Amer. Math. Soc. Transl., Vol. 180 (1997), pp. 219-227.

Links

Harry J. Smith, Table of n, a(n) for n = 3..200

Prog

(PARI) { for (n=3, 200, write("b060348.txt", n, " ", n^n * (n^2 - 1)/24); ) } \\ Harry J. Smith, Jul 04 2009

Crossrefs

Cf. A007830, A060349.

Sequence in context: A361047 A360777 A309472 * A365016 A367163 A363479

Adjacent sequences: A060345 A060346 A060347 * A060349 A060350 A060351

Keyword

nonn

Author

Noam Katz (noamkj(AT)hotmail.com), Mar 30 2001

Status

approved