## odd prime numbers

**J**ust read a puzzling fact in ** Le Monde** science leaflet: someone at the “Great Internet Mersenne Prime Search” (GIMPS) just found a prime number with 17 million digits and…it is the 48th prime number of the form 2p-1. Which just means it is an odd number. How odd a remark!!! And how wrong. In fact, the short news item meant that this is a Mersenne number, of the form 2

^{p}-1! Another victim of a hasty cut&paste, I presume…

February 10, 2013 at 12:25 am

Christian/Your reference to Mersenne primes reminds me the famous “Mersenne twister” by Matsumoto and Nishimura with a quite smaller p value (p=19937) but yet a very long period of (2^p)-1! This random number generator is implemented in R by default if I remember correctly: see also the package “randtoolbox” for additional generators.

February 10, 2013 at 11:09 am

Yes, indeed! This is the default generator in R (check with ?RNG).