Re: Changing Pure Function in Module

*To*: mathgroup at smc.vnet.net*Subject*: [mg29851] Re: Changing Pure Function in Module*From*: "Orestis Vantzos" <atelesforos at hotmail.com>*Date*: Fri, 13 Jul 2001 04:19:32 -0400 (EDT)*Organization*: National Technical University of Athens, Greece*References*: <9ijhui$ri5$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

squareQ[n_Integer] := IntegerQ[Sqrt[n]] Orestis <Flip at safebunch.com> wrote in message news:9ijhui$ri5$1 at smc.vnet.net... > 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 > > >