OFFSET
1,4
COMMENTS
a(n) = product of divisors d of n from set A001694 - powerful numbers.
Not multiplicative: a(4)*a(9) = 4*9=36 <> a(36) = 1296. - R. J. Mathar, Jun 07 2011
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..16385
FORMULA
EXAMPLE
For n = 12, set of such divisors is {1, 4}; a(12) = 1*4 = 4.
MAPLE
isA001694 := proc(n) for p in ifactors(n)[2] do if op(2, p) = 1 then return false; end if; end do; return true; end proc:
A183102 := proc(n) local a, d; a := 1 ; for d in numtheory[divisors](n) do if isA001694(d) then a := a*d; end if; end do; a ; end proc:
seq(A183102(n), n=1..70) ; # R. J. Mathar, Jun 07 2011
MATHEMATICA
powerfulQ[n_] := Min[FactorInteger[n][[All, 2]]] > 1;
a[n_] := Times @@ Select[Divisors[n], powerfulQ];
Table[a[n], {n, 1, 73}] (* Jean-François Alcover, Jun 01 2024 *)
PROG
(PARI) A183102(n) = { my(m=1); fordiv(n, d, if(ispowerful(d), m *= d)); m; }; \\ Antti Karttunen, Oct 07 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 25 2010
STATUS
approved