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A064031 Product of non-unitary divisors of n!. 1
1, 1, 1, 576, 207360000, 26956124946896309452800000000000, 2841003716170671644367609186370356458508919205193278721884160000000000000000000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10

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 *)

CROSSREFS

Cf. A048656, A048657, A061537, A061538, A000142, A048105, A000005, A034444.

Sequence in context: A068277 A068289 A159055 * A013911 A198778 A198777

Adjacent sequences:  A064028 A064029 A064030 * A064032 A064033 A064034

KEYWORD

nonn

AUTHOR

Labos Elemer, Sep 13 2001

STATUS

approved

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Last modified August 18 08:57 EDT 2019. Contains 326077 sequences. (Running on oeis4.)