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Number TheorySuperchallengeModular Arithmetic

Modular Arithmetic · Superchallenge problem

The quadratic f(n)=n2+5n+16f(n) = n^2 + 5n + 16 is a multiple of 1313 now and then. Among n=1,…,1000n = 1, \ldots, 1000, how many times is f(n)f(n) a multiple of 132=16913^2 = 169?