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<TITLE>Re: n => 2n+1 to get prime: seed = 73</TITLE>
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<DIV>OK, Don, thank you very much indeed, and <BR>A052333 is even more
relevant, also see <A
href="http://www.prothsearch.net/rieselprob.html">http://www.prothsearch.net/rieselprob.html</A><BR>WOW,
I've rediscovered (once again) the known problem ;-( Zak </DIV>
<DIV> </DIV>
<DIV>PS Dear Seqfans, do you see all this rubbish in my address?</DIV>
<DIV>If so, it's Hebrew letters, and I can't do anything, sorry</DIV>
<DIV> </DIV>
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<DIV><FONT size=2><B>From:</B> Don Reble [mailto:djr@nk.ca] <BR><B>Sent:</B>
Fri 3/11/2005 3:47 PM <BR><B>Subject:</B> Re: n => 2n+1 to get prime:
seed = 73<BR></FONT><FONT size=2>> Dear Seqfans,<BR>> The operation n
=> 2n+1 quickly gives primes for most "seed" values of n.<BR>> But for
some seeds, the transformed numbers keep being composite.<BR>> The first
"tough" number is n=73.<BR>> Can the n =>2n+1 transformation, in this
particular case,<BR>> lead to prime number (and
when?),<BR><BR>Starting from 73, the 2552nd number (74 * 2^2552 - 1) is prime.
It's a<BR>771-digit number which begins and ends 12525...16703.<BR><BR>See
also A040081.<BR>Don Reble
djr@nk.ca<BR><BR></FONT></DIV></BLOCKQUOTE>
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