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I want to calculate the sum of product of Fibonacci number for a given $n$. That is, for given $n$, say

$$F_1 F_n + F_2 F_{n-1} + F_3 F_{n-2} + F_4 F_{n-3} + F_5 F_{n-4} + \cdots.$$

what should be my approach.

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    Have you tried calculating the first few examples? What did you get? Do you see a pattern? And what does this have to do with math-software?2012-09-03
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    math-software is probably such a common noob tag because it is one of the first auto-suggests when you type "math" in the required tag field, and also because the people asking for math help might want to eventually use the answer to their math problem in a software. Hence math-software, the perfect combination.2012-09-03
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    you can use the generating function $f(x)=\sum_k F_k x^k=x/(1-x-x^2)$ and notice that your numbers are the coefficients of the power series $f(x)^2$ - that will give you a recurrence relation2012-09-03
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    @user8268 not quite, because he doesnt include all the terms. Closer to half the coefficients, but even then, that's wrong when $n$ is odd.2012-09-03

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