Thread: 2/Pi

Srinivasa Ramanujan sent a sequence to G.H.Hardy in Cambridge:

1-5*(1/2)^3+p((1*3)/(2*4))^3-13((1*3*5)/(2*4*6))^3 + ...= 2/Pi



Any information about this infinite sequence is greatly appreciated...

Hardy said of Ramanujan's formulas, some of which he could not initially understand, that "a single look at them is enough to show that they could only be written down by a mathematician of the highest class. They must be true, for if they were not true, no one would have had the imagination to invent them."

found this from wikipedia.org. http://en.wikipedia.org/wiki/Ramanujan
also 1/Pi

I have never been able to understand how Ramanujuan was able to derive those limits.