a(n) = round(Pi*2^(n-1)) for n >= 1, a(0) = 1.

Terms

a(0) =1a(1) =3a(2) =6a(3) =13a(4) =25a(5) =50a(6) =101a(7) =201a(8) =402a(9) =804a(10) =1608a(11) =3217a(12) =6434a(13) =12868a(14) =25736a(15) =51472a(16) =102944a(17) =205887a(18) =411775a(19) =823550a(20) =1647099a(21) =3294199a(22) =6588397a(23) =13176795a(24) =26353589a(25) =52707179a(26) =105414357a(27) =210828714a(28) =421657428a(29) =843314857