Primes of the form 3*6^k - 1.A186104Primes of the form 3*6^k - 1.Terms a(0) =2a(1) =17a(2) =107a(3) =647a(4) =23327a(5) =139967a(6) =30233087a(7) =6530347007a(8) =39182082047External referencesoeis: A186104