## Re: [PrimeNumbers] Primes 17 below a power of ten

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• In a message dated 03/05/03 05:45:45 GMT Daylight Time, ... Nathan: by prove you presumably mean find probable prime , since there are only a few thousand
Message 1 of 3 , May 3, 2003
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In a message dated 03/05/03 05:45:45 GMT Daylight Time,
nrussell@... writes:

> If anyone is attempting to prove numbers of the form 10^n-17, please let me
> know.
>

Nathan: by "prove" you presumably mean "find probable prime", since there are
only a few thousand values of n that are /provable/ primes with today's best
technology (PRIMO).

At the Lifchitz's PRP site
http://ourworld.compuserve.com/homepages/hlifchitz/
you will observe that Milton Brown has made something of a speciality of the
form 10^n +- k, for smallish k. None of his (hundreds of) entries with n >=
10000 have k=-17, but he might be able to save you a valuable amount of (PFGW
or whatever) search time by divulging for which n ranges he has already
eliminated that value of k.

Mike Oakes

[Non-text portions of this message have been removed]
• ... Yes thank you. I am looking for numbers of reasonable size to prove with Primo this summer, in order to stay on the top 20 list for the program. There
Message 2 of 3 , May 3, 2003
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--On Saturday, May 03, 2003 3:19 AM -0400 mikeoakes2@... wrote:

> In a message dated 03/05/03 05:45:45 GMT Daylight Time,
> nrussell@... writes:
>
>
>> If anyone is attempting to prove numbers of the form 10^n-17, please let
>> me know.
>>
>
> Nathan: by "prove" you presumably mean "find probable prime", since there
> are only a few thousand values of n that are /provable/ primes with
> today's best technology (PRIMO).

Yes thank you. I am looking for numbers of "reasonable" size to prove with
Primo this summer, in order to stay on the top 20 list for the program.
There are two PRP of that form, and I just wanted to make sure nobody was
working on them.

So far we know that 10^n-17 is prime for n=1, 2, 3, 6 (found with PFGW),

n= 30, 40, 86, 128, 264, 639, and 912 (found with Primo and PFGW)

1932 will be known later today, and n=4650 and 5038 I am probably going to
test this summer.

Thanks for pointing me to Milton's work. I doubt he'll be beating me to
any finds since when I knew him he had little interest in actually proving
numbers. ;)

Nathan
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