Let be a discriminant,
(1) |
(2) | |||
(3) | |||
(4) |
See also Klein's Absolute Invariant, Pi
References
Borwein, J. M. and Borwein, P. B. ``Class Number Three Ramanujan Type Series for .''
J. Comput. Appl. Math. 46, 281-290, 1993.
Ramanujan, S. ``Modular Equations and Approximations to .'' Quart. J. Pure Appl. Math. 45, 350-372, 1913-1914.