Changing Pure Function in Module

*To*: mathgroup at smc.vnet.net*Subject*: [mg29822] Changing Pure Function in Module*From*: Flip at safebunch.com*Date*: Thu, 12 Jul 2001 02:52:35 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi All, thank you to all who continue to respond to all of my questions ... and there are always plenty of them. I have the following function embedded in the findD code below. a[1] =5; a[n_]:= a[n] = (-1)^(n+1) (Abs[a[n-1]]+2) In[225]:= findD[n_]:= Module[{c=0},NestWhile[(c++;(-1)^c(Abs[#]+2))&,5,JacobiSymbol[#,n]!=-1&]] I would like to change the pure function to use the following (cleaner) function that requires no starting value (and starts for n = 1). In[255]:= a[n_]:= a[n]= (-1)^(n+1)*(2n + 3) Also, it would be important to test n prior to calling findD. If n is a perfect square, findD will "never" converge. Is there a simple way to test if n is square and tell the user ... try again ... n is a perfect square. Again thank you for all of the help ... Wilson

**Follow-Ups**:**Re: Changing Pure Function in Module***From:*Daniel Lichtblau <danl@wolfram.com>