Partial sums of floor(3^n/5).

Terms

a(0) =0a(1) =1a(2) =6a(3) =22a(4) =70a(5) =215a(6) =652a(7) =1964a(8) =5900a(9) =17709a(10) =53138a(11) =159426a(12) =478290a(13) =1434883a(14) =4304664a(15) =12914008a(16) =38742040a(17) =116226137a(18) =348678430a(19) =1046035310a(20) =3138105950a(21) =9414317871a(22) =28242953636a(23) =84728860932a(24) =254186582820