Re: Mersenne: Re: 10,000,000 digit prime
> 33219281 _is_ prime, the status of 2^33219281 is (so far as I know) > not known at this time ... unless someone found a factor bigger than > my 2^40 search limit. I tried up to 46695341939693537 ~= 2^55, but no factor. Ciao, Alex. Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Re: 10,000,000 digit prime
On 29 Jun 99, at 18:06, Lucas Wiman wrote: > Therefore, to find the first one with 10^7 digits, we find ceil(10^7/log_10(2)) > which is 33219281. NO! The _correct_ formula is ceil((10^7-1)/log_10(2)) = 33219278. The point is that 2^n have 1 decimal digit for n < 4 ;-) As it happens, 33219278, 33219279 & 33219280 are all composite and therefore are not contenders for generating a Mersenne prime. 33219281 _is_ prime, the status of 2^33219281 is (so far as I know) not known at this time ... unless someone found a factor bigger than my 2^40 search limit. Regards Brian Beesley Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Re: 10,000,000 digit prime
>> The 10,000,000 digit prime would have an exponent of over >> 3010299.956, or 3010300 >> which is found by taking (log 2 * 10,000,000) > Actually, it's log10(2) * 10,000,000, which is a different number. Of > course, since I'm not at home, I can't figure out _that_ number offhand, > but see the posts from some weeks back to get the exact first exponent. The formula for determining the number of digits in Mp is p*log_10(2). Therefore, to find the first one with 10^7 digits, we find ceil(10^7/log_10(2)) which is 33219281. Yes, this is going in the FAQ... -Lucas Wiman Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Re: Mersenne: Re: 10,000,000 digit prime
At 15:55 28.06.99 +, Jonathan Zylstra wrote: >The 10,000,000 digit prime would have an exponent of over >3010299.956, or 3010300 >which is found by taking (log 2 * 10,000,000) Actually, it's log10(2) * 10,000,000, which is a different number. Of course, since I'm not at home, I can't figure out _that_ number offhand, but see the posts from some weeks back to get the exact first exponent. /* Steinar */ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
Mersenne: Re: 10,000,000 digit prime
The 10,000,000 digit prime would have an exponent of over 3010299.956, or 3010300 which is found by taking (log 2 * 10,000,000) J. Zylstra Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm
