Prove that there are an infinite number of distinct ordered pairs (m, n) of integers such that, for every positive integer t, the number mt + n is a triangular number if and only if t is a triangular number as well

http://rec-puzzles.org/new/sol.pl/competition/tests/math/putnam/putnam.1988 

This is the same as 1988 Putnam Problem B.6, and Old Original Oskar!'s solution is the same as the one given at the end of this reference. There is also a note at the very end that gives a characterization of all the possible "triangular pairs" (m,n)

Posted by Richard on 2004-10-27 04:49:38