A069897 Integer quotient of the largest and the smallest prime factors of n, with a(1) = 1.

1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 1, 2, 2, 5, 1, 1, 1, 6, 1, 3, 1, 2, 1, 1, 3, 8, 1, 1, 1, 9, 4, 2, 1, 3, 1, 5, 1, 11, 1, 1, 1, 2, 5, 6, 1, 1, 2, 3, 6, 14, 1, 2, 1, 15, 2, 1, 2, 5, 1, 8, 7, 3, 1, 1, 1, 18, 1, 9, 1, 6, 1, 2, 1, 20, 1, 3, 3, 21, 9, 5, 1, 2, 1, 11, 10, 23, 3, 1, 1, 3, 3, 2, 1

Offset: 1

Author

Labos Elemer, Apr 10 2002

Keywords

• nonn
• easy
• look

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A006530, A020639, A046665, A120454.

Programs

Mathematica

a[n_] := Module[{p = FactorInteger[n][[;;, 1]]}, Floor[p[[-1]] / p[[1]]]]; Array[a, 100] (* Amiram Eldar, Oct 24 2024 *)

PARI

A069897(n) = if(1==n,1, my(f = factor(n), lpf = f[1, 1], gpf = f[#f~, 1]); (gpf\lpf)); \\ Antti Karttunen, Sep 07 2018

Formula

a(n) = floor(A006530(n)/A020639(n)).

Extensions

Term a(1) = 1 prepended by Antti Karttunen, Sep 07 2018