Hello all, According to http://godplaysdice.blogspot.com/2008/05/little-number-theory-problem.html, the sequence http://www.research.att.com/~njas/sequences/A006863 has another interesting definition: gcd(p^(2n) - 1), taken over primes p > 2n+1. I am very sick - can't productively read it. Can someone check this and add the comment? Tanya