

A320389


Product_i prime(i)^e(i), where e are the nonzero exponents in the prime factorization of n, sorted in increasing order.


0



1, 2, 2, 4, 2, 6, 2, 8, 4, 6, 2, 18, 2, 6, 6, 16, 2, 18, 2, 18, 6, 6, 2, 54, 4, 6, 8, 18, 2, 30, 2, 32, 6, 6, 6, 36, 2, 6, 6, 54, 2, 30, 2, 18, 18, 6, 2, 162, 4, 18, 6, 18, 2, 54, 6, 54, 6, 6, 2, 150, 2, 6, 18, 64, 6, 30, 2, 18, 6, 30, 2, 108, 2, 6, 18, 18
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OFFSET

1,2


COMMENTS

Here the exponents are sorted in increasing order; if they are sorted in decreasing order, we get A046523: the smallest number with the same prime signature as n.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..20000


MAPLE

a:= n> (l> mul(ithprime(i)^l[i], i=1..nops(l)))(
sort(map(i> i[2], ifactors(n)[2]))):
seq(a(n), n=1..100); # Alois P. Heinz, Feb 18 2020


PROG

(PARI) a(n)=factorback(matconcat([primes(#n=factor(n)[, 2])~, vecsort(n)]))


CROSSREFS

Cf. A046523.
Sequence in context: A328707 A067824 A107067 * A046801 A316437 A137502
Adjacent sequences: A320386 A320387 A320388 * A320390 A320391 A320392


KEYWORD

nonn,changed


AUTHOR

M. F. Hasler, Oct 12 2018


STATUS

approved



