1-1-2-1-2-1-1-2-1-3-1-3-2-2-1-2-2-1-4-1-3-5-2-3-1-3-2-2-F-1-1-2-1-2-2-1-4-pi-

Question Number 128566 by Dwaipayan Shikari last updated on 08/Jan/21

1 + \frac{1}{2} {(\frac{1}{2} . \frac{1}{1!})}^{2} + \frac{1}{3} {(\frac{1.3}{2^{2}} . \frac{1}{2!})}^{2} + \frac{1}{4} {(\frac{1.3.5}{2^{3}} . \frac{1}{3!})}^{2} + \dots =_{2} F_{1} (\frac{1}{2}, \frac{1}{2}; 2; 1) = \frac{4}{π}

Commented by Dwaipayan Shikari last updated on 08/Jan/21

I've posted this question on brilliant https://brilliant.org/problems/in-search-of