Putnam 2009 B6
Source:
December 7, 2009
Putnaminductioncollege contests
Problem Statement
Prove that for every positive integer there is a sequence of integers with a_0\equal{}0 and a_{2009}\equal{}n such that each term after is either an earlier term plus for some nonnnegative integer or of the form for some earlier positive terms and [Here denotes the remainder when is divided by so ]