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

Author

Giovanni Teofilatto, Nov 12 2005

Keywords

• nonn

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

Crossrefs

Bisection of A006530.

Programs

Mathematica

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

Extensions

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