a(n) = 836*2^n - 771.

Terms

a(0) =65a(1) =901a(2) =2573a(3) =5917a(4) =12605a(5) =25981a(6) =52733a(7) =106237a(8) =213245a(9) =427261a(10) =855293a(11) =1711357a(12) =3423485a(13) =6847741a(14) =13696253a(15) =27393277a(16) =54787325a(17) =109575421a(18) =219151613a(19) =438303997a(20) =876608765a(21) =1753218301a(22) =3506437373a(23) =7012875517a(24) =14025751805a(25) =28051504381a(26) =56103009533a(27) =112206019837a(28) =224412040445a(29) =448824081661