MathDB
2010 Algebra #3: Recursive Sequence

Source:

July 15, 2012

Problem Statement

Let S0=0S_0=0 and let SkS_k equal a1+2a2+…+kaka_1+2a_2+\ldots+ka_k for k≥1k\geq 1. Define aia_i to be 11 if Si−1<iS_{i-1}<i and −1-1 if Si−1≥iS_{i-1}\geq i. What is the largest k≤2010k\leq 2010 such that Sk=0S_k=0?
Back to ProblemsView on AoPS