MathDB
calculating the summation

Source: Indonesia IMO 2007 TST, Stage 2, Test 1, Problem 4

November 15, 2009
combinatorics proposedcombinatorics

Problem Statement

Let n n and k k be positive integers. Please, find an explicit formula for ∑y1y2…yk, \sum y_1y_2 \dots y_k, where the summation runs through all k\minus{}tuples positive integers (y1,y2,…,yk) (y_1,y_2,\dots,y_k) satisfying y_1\plus{}y_2\plus{}\dots\plus{}y_k\equal{}n.
Back to ProblemsView on AoPS