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2n! / number of divisors of n.
0

%I #11 Dec 15 2017 17:35:16

%S 2,2,6,16,120,360,5040,20160,241920,1814400,39916800,159667200,

%T 6227020800,43589145600,653837184000,8369115955200,355687428096000,

%U 2134124568576000,121645100408832000,810967336058880000

%N 2n! / number of divisors of n.

%t (2#!)/DivisorSigma[0,#]&/@Range[20] (* _Harvey P. Dale_, Feb 04 2011 *)

%o (PARI) for(n=1,23,print((2*n!)/numdiv(n)))

%K easy,nonn

%O 1,1

%A _Jason Earls_, Jul 20 2001