MathDB
Putnam 2010 B6

Source:

December 6, 2010
Putnamlinear algebramatrixalgebrapolynomialinductionvector

Problem Statement

Let AA be an n×nn\times n matrix of real numbers for some n1.n\ge 1. For each positive integer k,k, let A[k]A^{[k]} be the matrix obtained by raising each entry to the kkth power. Show that if Ak=A[k]A^k=A^{[k]} for k=1,2,,n+1,k=1,2,\cdots,n+1, then Ak=A[k]A^k=A^{[k]} for all k1.k\ge 1.