Where can I find some nice formulas for the lambda invariant of an elliptic curve? I vaguely recall there's a nice product formula in terms of $q$, but a google search didn't give me much. Also, are there other formulas that express the lambda-function in terms of $q$ or give a precise formula for the coefficients of its $q$-expansion?
At the moment I have two books at my disposal: Silverman's advanced topics in the arithmetic of elliptic curves and Diamond&Shurman. Silverman gives nice formulas for the j-invariant, but I can't find much on the lambda-invariant, unfortunately.