De transformatione seriei divergentis 1 - mx + m(m+n)x^2 -   m(m+n)(m+2n)x^3 + etc. in fractionem continuam
  In this paper, Euler transforms the divergent series in the title, and thereby dervies the well known continued fraction expansion for pi/4 from Leibniz's series. The paper is translated from Euler's Latin originial into German. 
Leonhard Euler, Artur Diener, Alexander Aycock
math.HO