OFFSET
1,6
COMMENTS
For n = 12, the set of such divisors is {6, 12}; a(12) = 6*12 = 72.
a(n) is also the product of divisors d of n such that d is not equal to p^k where p = prime, k >=1. For n = 12, the set of such divisors is {1, 6, 12}; a(12) = 1*6*12 = 72.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
MAPLE
A183092 := proc(n) local a, d; a := 1 ; for d in numtheory[divisors](n) minus {1} do if nops( numtheory[factorset](d)) > 1 then a := a*d; end if; end do: a ; end proc: # R. J. Mathar, Apr 14 2011
PROG
(PARI) A183092(n) = factorback(apply(d -> if(isprimepower(d), 1, d), divisors(n))); \\ Antti Karttunen, Aug 06 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 25 2010
EXTENSIONS
More terms from Antti Karttunen, Aug 06 2018
STATUS
approved