A111089 Largest prime factor of 2n.

2, 2, 3, 2, 5, 3, 7, 2, 3, 5, 11, 3, 13, 7, 5, 2, 17, 3, 19, 5, 7, 11, 23, 3, 5, 13, 3, 7, 29, 5, 31, 2, 11, 17, 7, 3, 37, 19, 13, 5, 41, 7, 43, 11, 5, 23, 47, 3, 7, 5, 17, 13, 53, 3, 11, 7, 19, 29, 59, 5, 61, 31, 7, 2, 13, 11, 67, 17, 23, 7, 71, 3, 73, 37, 5, 19, 11, 13, 79, 5, 3, 41, 83, 7

Offset

1,1

Comments

For composite indices we have a(n*m) = max(a(n), a(m)). - Stefan Steinerberger, Nov 13 2005

Same as A006530 except for initial term. - Franklin T. Adams-Watters, Jul 17 2008

Links

Table of n, a(n) for n=1..84.

Mathematica

Table[FactorInteger[2n][[ -1, 1]], {n, 100}] (* Ray Chandler, Nov 12 2005 *)

Crossrefs

Bisection of A006530.

Sequence in context: A162753 A307994 A238480 * A051664 A318884 A280990

Adjacent sequences: A111086 A111087 A111088 * A111090 A111091 A111092

Keyword

nonn

Author

Giovanni Teofilatto, Nov 12 2005

Extensions

Corrected and extended by Ray Chandler and Stefan Steinerberger, Nov 12 2005

Status

approved