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A064031
Product of non-unitary divisors of n!.
1
1, 1, 1, 576, 207360000, 26956124946896309452800000000000, 2841003716170671644367609186370356458508919205193278721884160000000000000000000000
OFFSET
1,4
LINKS
FORMULA
a(n) = A061538(n!) = (n!)^(A048105(n!)/2) = (n!)^((A000005(n!)-A034444(n!))/2)
EXAMPLE
n=6: 720 has 22 non-unitary divisors: a(6)=720^11=26956124946896309452800000000000
MATHEMATICA
a[n_] := (n!)^(DivisorSigma[0, n!]/2 - 2^(PrimePi[n]-1)); Array[a, 10] (* Amiram Eldar, Jul 16 2019 *)
KEYWORD
nonn
AUTHOR
Labos Elemer, Sep 13 2001
STATUS
approved