A073753 a(n) = A073752(A073752(n)), where A073752(n) = gcd(n/spf(n), n/gpf(n)), with spf(n) as the smallest and gpf(n) as the greatest prime factor of n (see A020639, A006530).

1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 3, 1, 1, 1, 1, 8, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 4, 1, 1, 1, 1, 1, 3, 1, 2, 1, 1, 1, 1, 1, 1, 1, 16, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 4, 9, 1, 1, 1, 1, 1, 1, 2, 1, 3, 1, 1, 1, 1, 1, 8, 1, 1, 1, 1, 1, 1, 1, 2

Offset

1,8

Comments

a(n) = A062378(n) for n<90, but a(90)=3 <> A062378(90)=1.

Links

Antti Karttunen, Table of n, a(n) for n = 1..10000

Formula

a(n) = A073752(A073752(n)).

Mathematica

A073752[n_] := With[{f = FactorInteger[n][[All, 1]]}, GCD[n/f[[1]], n/f[[-1]]]];
a[n_] := A073752[A073752[n]];
Array[a, 100] (* Jean-François Alcover, Dec 03 2021 *)

Crossrefs

Cf. A006530, A020639, A073752.

Differs from A062378 for the first time at n=90.

Sequence in context: A204133 A342017 A062378 * A290602 A255404 A078090

Adjacent sequences: A073750 A073751 A073752 * A073754 A073755 A073756

Keyword

nonn

Author

Reinhard Zumkeller, Aug 07 2002

Extensions

Name edited by Antti Karttunen, Sep 23 2017

Status

approved