(x^2 + x + 1)^n
Source: IMO ShortList 1988, Problem 2, Bulgaria 3, Problem 3 of ILL
October 22, 2005
algebrapolynomialfunctionbinomial coefficientsgenerating functionsIMO Shortlist
Problem Statement
Let be a positive integer. Find the number of odd coefficients of the polynomial
u_n(x) \equal{} (x^2 \plus{} x \plus{} 1)^n.