%I #13 Jun 11 2014 17:22:17
%S 1,4,2,8,40,120,168,6720,120960,44800,6652800,14515200,415134720
%N Denominator of probability that 2 elements of S_n chosen at random (with replacement) generate S_n.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SymmetricGroup.html">Symmetric Group.</a>
%e Values for n=1,2,3,... are 1, 3/4, 1/2, 3/8, 19/40, 53/120, 103/168, 4111/6720, 78293/120960, ...
%Y Probability is A040173/A040174 = A040175/n!.
%K nonn,frac,nice,more
%O 1,2
%A _Dan Hoey_
%E a(10)-a(13) from _Stephen A. Silver_, Feb 21 2013