a(n) = 99*2^n - 45 (n>=0).

Terms

a(0) =54a(1) =153a(2) =351a(3) =747a(4) =1539a(5) =3123a(6) =6291a(7) =12627a(8) =25299a(9) =50643a(10) =101331a(11) =202707a(12) =405459a(13) =810963a(14) =1621971a(15) =3243987a(16) =6488019a(17) =12976083a(18) =25952211a(19) =51904467a(20) =103808979a(21) =207618003a(22) =415236051a(23) =830472147a(24) =1660944339a(25) =3321888723a(26) =6643777491a(27) =13287555027a(28) =26575110099a(29) =53150220243