a(n) = 31*2^n + 1.

Terms

a(0) =32a(1) =63a(2) =125a(3) =249a(4) =497a(5) =993a(6) =1985a(7) =3969a(8) =7937a(9) =15873a(10) =31745a(11) =63489a(12) =126977a(13) =253953a(14) =507905a(15) =1015809a(16) =2031617a(17) =4063233a(18) =8126465a(19) =16252929a(20) =32505857a(21) =65011713a(22) =130023425a(23) =260046849a(24) =520093697a(25) =1040187393a(26) =2080374785a(27) =4160749569a(28) =8321499137a(29) =16642998273