Need Help with Sow within While Loop

*To*: mathgroup at smc.vnet.net*Subject*: [mg124892] Need Help with Sow within While Loop*From*: KenR <ramsey2879 at msn.com>*Date*: Sat, 11 Feb 2012 06:35:09 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com

My Code is short so I will include it for reference Caa = 1049001; Reap[While[Caa < 1050001, Co = 1; S0 = 2; S1 = 3; While[Co < ((Caa-1)/2),Temp = Mod[6 S1 - S0 - 6,Caa];If[Temp <= 1,Break[]]; S0=S1;S1=Temp;Co++]; n = ((Caa-1)/2) - Co; If[n<2,If[n>0, Sow[Caa]]]; Caa++;Caa++]] First I noted that this loop took about one hour to find 31 Primes in the above range. This code appears to pick only primes but it only picks about 34% of the primes. I am trying to find a false hit but out of some 30,000 hits in the range from 3 up to 1050000 none were composite numbers. I would like to know if the code could be spead up. Also, how can I avoid reaping a list within a list such as {null, {{a,b,c...}}} when I want {a,b,c...}.