> ...Let f(x)=3x+2. ... > > 2, 3, 5, 29, 1129, 10009, 575119 > > ...if p = 29 then p,f(p),f(f(p)),f(f(f(p))) are primes. > > Has anyone seen another such sequence with a different f? A057331 -- Don Reble djr at nk.ca