> From: George Louis <georgelo...@cox.net> > Subject: [Prime] Large prime numbers
Dear George, I'm glad you're interested in finding large prime numbers but, as Ian Halliday has explained, you seem to have misunderstood the actual magnitude of the prime numbers for which the Electronic Frontier Foundation is offering prizes. Just in case there is any lingering misunderstanding, let me offer an additional explanation. If you look at http://www.eff.org/awards/coop, you will find that the prizes are given for discovering prime numbers with at least certain numbers _of decimal digits_. That is, the numbers 1,000,000 through 1,000,000,000 on that page are not the sizes of the prime numbers to be found; they are the sizes _of the decimal representations_, when written out in decimal form, of the prime numbers to be found. "at least 1,000,000,000 decimal digits" does not refer to a number greater than 10 to the 9th power; it refers to a number _whose number of decimal digits is greater than 10 to the 9th power_. That would be a number greater than 10 to the 999,999,999th power. Perhaps you were led astray by a common practice in the Mersenne number community: we typically refer to numbers by their power-of-2 exponents. That is, M43112609 does not refer to the prime number 43,112,609; it refers to the prime number which is 2 to the 43112609th power minus 1 (which has 12,978,189 decimal digits when written in decimal form). Making it even more confusing for newcomers is that we often omit the "M", and refer to "43112609" (an 8-digit number) when what we really mean is "2 to the 43112609th power minus 1" (a 12,978,189-digit number). I hope this helps. Richard B. Woods _______________________________________________ Prime mailing list Prime@hogranch.com http://hogranch.com/mailman/listinfo/prime
