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A304339 Fixed point of f starting with n, where f(x) = x/(largest perfect power divisor of x). 2
1, 2, 3, 1, 5, 6, 7, 1, 1, 10, 11, 3, 13, 14, 15, 1, 17, 2, 19, 5, 21, 22, 23, 3, 1, 26, 1, 7, 29, 30, 31, 1, 33, 34, 35, 1, 37, 38, 39, 5, 41, 42, 43, 11, 5, 46, 47, 3, 1, 2, 51, 13, 53, 2, 55, 7, 57, 58, 59, 15, 61, 62, 7, 1, 65, 66, 67, 17, 69, 70, 71, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

All terms are squarefree numbers. First differs from A304328 at a(500) = 1, A304328(500) = 4.

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..1000

EXAMPLE

f maps 500 -> 4 -> 1 -> 1, so a(500) = 1.

MATHEMATICA

radQ[n_]:=And[n>1, GCD@@FactorInteger[n][[All, 2]]===1];

op[n_]:=n/Last[Select[Divisors[n], !radQ[#]&]];

Table[FixedPoint[op, n], {n, 200}]

PROG

(PARI) a(n)={while(1, my(m=1); fordiv(n, d, if(ispower(d), m=max(m, d))); if(m==1, return(n)); n/=m)} \\ Andrew Howroyd, Aug 26 2018

CROSSREFS

Cf. A000961, A001597, A001694, A005117, A007916, A052485, A052486, A059404, A091050, A160400, A203025, A294068, A303707, A304327, A304328.

Sequence in context: A182938 A055231 A304328 * A160400 A072400 A007913

Adjacent sequences:  A304336 A304337 A304338 * A304340 A304341 A304342

KEYWORD

nonn

AUTHOR

Gus Wiseman, May 11 2018

STATUS

approved

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Last modified February 20 08:44 EST 2019. Contains 320325 sequences. (Running on oeis4.)