a(n) = 512n - 1.

Terms

a(0) =511a(1) =1023a(2) =1535a(3) =2047a(4) =2559a(5) =3071a(6) =3583a(7) =4095a(8) =4607a(9) =5119a(10) =5631a(11) =6143a(12) =6655a(13) =7167a(14) =7679a(15) =8191a(16) =8703a(17) =9215a(18) =9727a(19) =10239a(20) =10751a(21) =11263a(22) =11775a(23) =12287a(24) =12799a(25) =13311a(26) =13823a(27) =14335a(28) =14847a(29) =15359