OFFSET
1,4
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10
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
KEYWORD
nonn
AUTHOR
Labos Elemer, Sep 13 2001
STATUS
approved