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This is an identity put forward by Ramanujan (often used as "proof" of his genius):

$$ \frac{2\sqrt{2}}{9801} \sum_{k=0}^\infty \frac{ (4k)! (1103+26390k) }{ (k!)^4 396^{4k} } = \frac1{\pi} $$

How does one go about proving this? Alternatively, what does one need to know to be able to do so?

Any help is appreciated.


marked as duplicate by 6005, Mark Bennet, Davide Giraudo, Vedran Šego, dtldarek Sep 27 '13 at 20:36

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  • $\begingroup$ Thanks! The links are really good, and since this has been marked as a dup I'll accept your answer. $\endgroup$ – Soham Chowdhury Sep 28 '13 at 2:38
  • 2
    $\begingroup$ @SohamChowdhury Hail Ramanujan $\endgroup$ – Shobhit Sep 28 '13 at 3:24

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