OFFSET
1,4
COMMENTS
Not multiplicative, as a(4)*a(9) <> a(36). - 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
isA001597 := proc(n) local e ; e := seq(op(2, p), p=ifactors(n)[2]) ; return ( igcd(e) >=2 ) ; end proc:
A183104 := proc(n) local a, d; a := 1 ; for d in numtheory[divisors](n) do if isA001597(d) then a := a*d; end if; end do; a ; end proc:
seq(A183104(n), n=1..72) ; # R. J. Mathar, Jun 07 2011
MATHEMATICA
perfPQ[n_]:=GCD@@FactorInteger[n][[All, 2]]>1; Table[Times@@Select[Divisors[n], perfPQ[#]&], {n, 120}] (* Harvey P. Dale, Mar 07 2024 *)
PROG
(PARI) A183104(n) = { my(m=1); fordiv(n, d, if(ispower(d), m *= d)); m; }; \\ Antti Karttunen, Oct 07 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Jaroslav Krizek, Dec 25 2010
STATUS
approved