An interesting fact about primes
14/03/2012 10:00
Mathematicians of XVIIIth century proved that numbers 31; 331; 3331; 33331; 333331; 3333331; 33333331 are primes. It was a big temptation to think that all numbers of such kind are primes. But the next number is not a prime.
333333331 = 17 * 19607843