Finding length in recursive definition?

*To*: mathgroup at smc.vnet.net*Subject*: [mg60877] Finding length in recursive definition?*From*: "Jose Reckoner" <reckoner at gmail.com>*Date*: Sat, 1 Oct 2005 02:55:52 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

I have something like: f[1] = 1 f[2] = 3 f[n_] := f[n] = f[n - 1] + f[n - 2] and in the course of work, f[n] gets evaluated an unknown number of times resulting in >> ?f f[1] = 1 f[2] = 3 f[3] = 4 f[n_] := f[n] = f[n - 1] + f[n - 2] I want to figure out the greatest integer n such that f[n] has already been computed and is stored. In this case, it is 3. How can I do this? Thanks! Jose