Divisors of 2^39 - 1.

Terms

a(0) =1a(1) =7a(2) =79a(3) =553a(4) =8191a(5) =57337a(6) =121369a(7) =647089a(8) =849583a(9) =4529623a(10) =9588151a(11) =67117057a(12) =994133479a(13) =6958934353a(14) =78536544841a(15) =549755813887