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a(n) = the product of divisors of product of divisors of n.
3

%I #12 Sep 08 2022 08:46:18

%S 1,2,3,64,5,10077696,7,2097152,729,1000000000,11,

%T 2116471057875484488839167999221661362284396544,13,20661046784,

%U 38443359375,36028797018963968,17,52655678627806560751363688397557640770141543227981824,19

%N a(n) = the product of divisors of product of divisors of n.

%F a(n) = A007955(A007955(n)).

%F For p = primes (A000040); a(p) = p.

%F For c = composites (A002808); a(c) = perfect powers of the form m^k where m > 1 and k >= 2 (terms of A001597).

%e For n = 4; a(n) = product of divisors (1*2*4) = 1*2*4*8 = 64.

%t Table[Nest[Times @@ Divisors@ # &, n, 2], {n, 19}] (* _Michael De Vlieger_, Jan 06 2017 *)

%o (Magma) [&*[d: d in Divisors(&*[d: d in Divisors(n)])]: n in [1..100]]

%Y Cf. A000040, A001597, A002808, A007955, A280581.

%K nonn

%O 1,2

%A _Jaroslav Krizek_, Jan 06 2017