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A280582 a(n) = the product of divisors of product of divisors of n. 3
1, 2, 3, 64, 5, 10077696, 7, 2097152, 729, 1000000000, 11, 2116471057875484488839167999221661362284396544, 13, 20661046784, 38443359375, 36028797018963968, 17, 52655678627806560751363688397557640770141543227981824, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..19.

FORMULA

a(n) = A007955(A007955(n)).

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

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

EXAMPLE

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

MATHEMATICA

Table[Nest[Times @@ Divisors@ # &, n, 2], {n, 19}] (* Michael De Vlieger, Jan 06 2017 *)

PROG

(MAGMA) [&*[d: d in Divisors(&*[d: d in Divisors(n)])]: n in [1..100]]

CROSSREFS

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

Sequence in context: A293041 A284755 A061452 * A037426 A004854 A015169

Adjacent sequences:  A280579 A280580 A280581 * A280583 A280584 A280585

KEYWORD

nonn

AUTHOR

Jaroslav Krizek, Jan 06 2017

STATUS

approved

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Last modified July 2 16:19 EDT 2020. Contains 335404 sequences. (Running on oeis4.)