Cototient of 2^n + 1.

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =1a(5) =13a(6) =17a(7) =45a(8) =1a(9) =189a(10) =225a(11) =685a(12) =257a(13) =2733a(14) =3841a(15) =12969a(16) =1a(17) =43693a(18) =75521a(19) =174765a(20) =61697a(21) =731817a(22) =848897a(23) =2796205a(24) =262145a(25) =13304433a(26) =14802689a(27) =49449609a(28) =15790337a(29) =185023425