OFFSET
1,2
COMMENTS
Not multiplicative since a(2)*a(3) <> a(6). - 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 {2, 3, 6, 12}; a(12) = 1*2*3*6*12 = 432.
MAPLE
isA001597 := proc(n) local e ; e := seq(op(2, p), p=ifactors(n)[2]) ; return ( igcd(e) >=2 ) ; end proc:
A183105 := proc(n) local a, d; a := 1 ; for d in numtheory[divisors](n) do if not isA001597(d) then a := a*d; end if; end do; a ; end proc:
seq(A183105(n), n=1..72) ; # R. J. Mathar, Jun 07 2011
MATHEMATICA
perfectPowerQ[n_] := GCD @@ FactorInteger[n][[All, 2]] > 1;
a[n_] := Times @@ Select[Divisors[n], !perfectPowerQ[#]&];
Table[a[n], {n, 1, 72}] (* Jean-François Alcover, May 31 2024 *)
PROG
(PARI) A183105(n) = { my(m=1); fordiv(n, d, if(!ispower(d), m *= d)); m; }; \\ Antti Karttunen, Oct 07 2017
CROSSREFS
KEYWORD
nonn,look
AUTHOR
Jaroslav Krizek, Dec 25 2010
STATUS
approved