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Problem #375

Sigma Sigma Sigma Boy

Let f(i) denote the i^{th} Fibonacci number (f(0)=0,f(1)=1). Based on the given definition, find the value of S(1234567) modulo 1,000,000,007.

S(n)=\sum_{i=1}^{n} \sum_{j=0}^{i - 1} \sum_{k=j + 1}^{i} f(i) \cdot f(j) \cdot f(k)

Contributed by Tanay Kapadia

Solved by 6 users

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