A064030 - OEIS

%I #6 Jul 16 2019 06:15:29

%S 1,2,36,576,207360000,268738560000,416336312719673760153600000000,

%T 6984964247141514123629140377600000000,

%U 300679807141675805997423113304381849600000000

%N Product of unitary divisors of n!.

%H Amiram Eldar, <a href="/A064030/b064030.txt">Table of n, a(n) for n = 1..17</a>

%F a(n)=(n!)^(A034444(n!)/2)

%e n = 6 has 8 unitary divisors:{16,45,9,80,5,144,1,720}, a(6) = 720^4 = 268738560000

%t a[n_] := (n!)^(2^(PrimePi[n]-1)); Array[a, 10] (* _Amiram Eldar_, Jul 16 2019 *)

%Y Cf. A048656, A048657, A061537, A061538, A000142.

%K nonn

%O 1,2

%A _Labos Elemer_, Sep 13 2001