a(n) = abs(2^n-127).

Terms

a(0) =126a(1) =125a(2) =123a(3) =119a(4) =111a(5) =95a(6) =63a(7) =1a(8) =129a(9) =385a(10) =897a(11) =1921a(12) =3969a(13) =8065a(14) =16257a(15) =32641a(16) =65409a(17) =130945a(18) =262017a(19) =524161a(20) =1048449a(21) =2097025a(22) =4194177a(23) =8388481a(24) =16777089a(25) =33554305a(26) =67108737a(27) =134217601a(28) =268435329a(29) =536870785