A060902 Number of ordered factorizations of the identity permutation in the symmetric group S_n into 2n-2 transpositions such that the factors generate S_n.

1, 24, 2880, 1008000, 783820800, 1150082841600, 2856658246041600, 11119228380868608000, 64023737057280000000000, 521514152055397400739840000, 5799596870820600732828303360000

Offset

2,2

References

I. P. Goulden and D. M. Jackson, Transitive factorizations into transpositions and holomorphic mappings on the sphere, Proc. AMS., 125 (1997), 51-60.

Links

Harry J. Smith, Table of n, a(n) for n=2,...,100

I. P. Goulden and D. M. Jackson, Transitive factorizations into transpositions and holomorphic mappings on the sphere, Proc. AMS., 125 (1997), 51-60.

Formula

a(n) = (2n-2)! * n^(n-3).

Example

a(2) = 1 because the only such factorization is (12)(12) = 1

Prog

(PARI) { for (n=2, 100, write("b060902.txt", n, " ", (2*n - 2)! * n^(n - 3)); ) } \\ Harry J. Smith, Jul 14 2009

Crossrefs

Sequence in context: A209708 A266870 A277003 * A090444 A205795 A222852

Adjacent sequences: A060899 A060900 A060901 * A060903 A060904 A060905

Keyword

nonn,easy

Author

Ahmed Fares (ahmedfares(AT)my-deja.com), May 05 2001

Extensions

More terms from Jason Earls, May 08 2001

Status

approved