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

Terms

a(0) =0a(1) =1a(2) =3a(3) =8a(4) =24a(5) =73a(6) =219a(7) =656a(8) =1968a(9) =5905a(10) =17715a(11) =53144a(12) =159432a(13) =478297a(14) =1434891a(15) =4304672a(16) =12914016a(17) =38742049a(18) =116226147a(19) =348678440a(20) =1046035320a(21) =3138105961a(22) =9414317883a(23) =28242953648a(24) =84728860944a(25) =254186582833