login
A320389
Product_i prime(i)^e(i), where e are the nonzero exponents in the prime factorization of n, sorted in increasing order.
1
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
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
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: A347458 A107067 A331580 * A046801 A348717 A316437
KEYWORD
nonn
AUTHOR
M. F. Hasler, Oct 12 2018
STATUS
approved