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A postage problem. (English) Zbl 1250.97004
Summary: Let a and b be two positive integers greater than 1. Suppose that a and b are relatively prime. Then, there exists a positive integer N such that for all integers nN, there exist nonnegative integers x and y such that n=ax+by. Furthermore, it is not possible to find nonnegative integers for x and y such that N-1=ax+by.
MSC:
97F60Number theory (educational aspects)
11D04Linear diophantine equations
97N70Discrete mathematics (educational aspects)