MathDB
A 27

Source:

May 25, 2007
modular arithmeticbinomial coefficientsDivisibility Theory

Problem Statement

Show that the coefficients of a binomial expansion (a+b)n(a+b)^n where nn is a positive integer, are all odd, if and only if nn is of the form 2kāˆ’12^{k}-1 for some positive integer kk.