MathDB
Putnam 2004 A4

Source:

December 11, 2004
Putnamalgebrapolynomialcollege contests

Problem Statement

Show that for any positive integer nn there is an integer NN such that the product x1x2xnx_1x_2\cdots x_n can be expressed identically in the form x1x2xn=i=1Nci(ai1x1+ai2x2++ainxn)nx_1x_2\cdots x_n=\sum_{i=1}^Nc_i(a_{i1}x_1+a_{i2}x_2+\cdots +a_{in}x_n)^n where the cic_i are rational numbers and each aija_{ij} is one of the numbers, 1,0,1.-1,0,1.