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%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
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