Re: [math-fun] Prime question
Was that calculation done with this definition, or the corrected one he posted afterwards? (I.e. deletion of a digit yields another *good* prime, not just a prime.)
On Tue, 25 Feb 2003, David Wilson wrote:
Let p be a good prime if it has only one digit or else a single digit can be deleted leaving a prime. Should we expect there to be a largest good prime?
My guess is no. I chose 10 random 200 digit primes and found that 5 of them were good primes. I did it again and found that out of 10 all 10 were good!
This was done using Maple's probabilistic primality test "isprime". Actually in each case I first selected a ramdom 200 digit positive integer and then used the next 10 primes in a row to test for goodness.
--Edwin
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-- Mike Stay staym@clear.net.nz
On Wed, 26 Feb 2003, Mike Stay wrote:
Was that calculation done with this definition, or the corrected one he posted afterwards? (I.e. deletion of a digit yields another *good* prime, not just a prime.)
Sorry. I missed the other definition. I used the definition below [A prime is good if it is a single digit or there is a digit whose removal leaves a prime.] --Edwin
On Tue, 25 Feb 2003, David Wilson wrote:
Let p be a good prime if it has only one digit or else a single digit can be deleted leaving a prime. Should we expect there to be a largest good prime?
My guess is no. I chose 10 random 200 digit primes and found that 5 of them were good primes. I did it again and found that out of 10 all 10 were good!
This was done using Maple's probabilistic primality test "isprime". Actually in each case I first selected a ramdom 200 digit positive integer and then used the next 10 primes in a row to test for goodness.
--Edwin
participants (2)
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Edwin Clark -
Mike Stay