a(n) = A128018(n) + 1.

Terms

a(0) =2a(1) =-1a(2) =-7a(3) =-7a(4) =17a(5) =65a(6) =65a(7) =-127a(8) =-511a(9) =-511a(10) =1025a(11) =4097a(12) =4097a(13) =-8191a(14) =-32767a(15) =-32767a(16) =65537a(17) =262145a(18) =262145a(19) =-524287a(20) =-2097151a(21) =-2097151a(22) =4194305a(23) =16777217a(24) =16777217a(25) =-33554431a(26) =-134217727a(27) =-134217727a(28) =268435457a(29) =1073741825