Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

Lucas Lehmer prime Mersenne test

3 views
Skip to first unread message

Roger Bagula

unread,
Nov 18, 2004, 1:52:28 AM11/18/04
to
The real problem with this test is that Mersenne
number are grossly big, but the Lucas-Lehmer test recurrence is just
bigger much too fast.
I can't get it above n=8 in real time.
The Lucas -Lehmer numbers are always ending in 4 and divisible by 2.

Clear[s,a,b]
(* Lucas Lehmer prime Mersenne test*)
s[n_]:=s[n]=s[n-1]^2-2
s[1]=4
digits=8
a=Table[s[n],{n,1,8}]

{4,14,194,37634,1416317954,2005956546822746114,
4023861667741036022825635656102100994,

16191462721115671781777559070120513664958590125499158514329308740975788034}

a/2

{2,7,97,18817,708158977,1002978273411373057,
2011930833870518011412817828051050497,

8095731360557835890888779535060256832479295062749579257164654370487894017}

(* Lucas -Lehmer test applied to Mersenne numbers*)

b=Table[If[Mod[s[Prime[n]-1],2^Prime[n]-1]==0, 2^Prime[n]-1,0],{n,1,digits}]
Respectfully, Roger L. Bagula

tf...@earthlink.net, 11759Waterhill Road, Lakeside,Ca 92040-2905,tel: 619-5610814 :
alternative email: rlb...@netscape.net
URL : http://home.earthlink.net/~tftn

0 new messages