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