MathDB
representation as sum of powers of 2, as floor of polynomial

Source: Putnam 1983 B2

September 15, 2021
algebracombinatoricspolynomial

Problem Statement

For positive integers nn, let C(n)C(n) be the number of representation of nn as a sum of nonincreasing powers of 22, where no power can be used more than three times. For example, C(8)=5C(8)=5 since the representations of 88 are: 8,4+4,4+2+2,4+2+1+1, and 2+2+2+1+1.8,4+4,4+2+2,4+2+1+1,\text{ and }2+2+2+1+1.Prove or disprove that there is a polynomial P(x)P(x) such that C(n)=P(n)C(n)=\lfloor P(n)\rfloor for all positive integers nn.