A040174 Denominator of probability that 2 elements of S_n chosen at random (with replacement) generate S_n.

1, 4, 2, 8, 40, 120, 168, 6720, 120960, 44800, 6652800, 14515200, 415134720

Offset

1,2

Links

Table of n, a(n) for n=1..13.

Eric Weisstein's World of Mathematics, Symmetric Group.

Example

Values for n=1,2,3,... are 1, 3/4, 1/2, 3/8, 19/40, 53/120, 103/168, 4111/6720, 78293/120960, ...

Crossrefs

Probability is A040173/A040174 = A040175/n!.

Sequence in context: A204449 A172393 A245340 * A084477 A046589 A072562

Adjacent sequences: A040171 A040172 A040173 * A040175 A040176 A040177

Keyword

nonn,frac,nice,more

Author

Dan Hoey

Extensions

a(10)-a(13) from Stephen A. Silver, Feb 21 2013

Status

approved