Is there a general formula for something like(adsbygoogle = window.adsbygoogle || []).push({});

[itex]\sum_{n=0}^{\infty} \left( f(n) \times g(n) \right)[/itex]

For example, what is

[itex]\sum_{n=0}^{\infty} \left( 3^n \times \frac{n!}{n^2} \right)[/itex]

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# Summation of a Product of Functions

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