Ramanujan R and S
With (Mathematica's QPochhammer[a,q]), the expressions and represent Roger–Ramanujan and Roger–Ramanujan , also representable as and , using Mathematica's notation for continued fractions (the ContinuedFractionK function). In 1919, months before his death, Ramanujan wrote down various elegant results for this function in what became the "lost notebook."[more]
Ramanujan claimed that many equations like can be expressed in terms of radicals . This notebook collects many of these results.[less]
 S. Ramanujan, The Lost Notebook and Other Unpublished Papers, New Delhi: Narosa Publishing House, 1988 p. 210.
 G. E. Andrews and B. C. Berndt, Ramanujan's Lost Notebook: Part I, New York: Springer, 2005 pp. 58–84.
 Wikipedia. "Ramanujan's Lost Notebook." (Apr 9, 2013) en.wikipedia.org/wiki/Ramanujan%27s_lost _notebook.