Powers of sqrt(3) rounded up.

Terms

a(0) =1a(1) =2a(2) =3a(3) =6a(4) =9a(5) =16a(6) =27a(7) =47a(8) =81a(9) =141a(10) =243a(11) =421a(12) =729a(13) =1263a(14) =2187a(15) =3788a(16) =6561a(17) =11364a(18) =19683a(19) =34092a(20) =59049a(21) =102276a(22) =177147a(23) =306828a(24) =531441a(25) =920483a(26) =1594323a(27) =2761449a(28) =4782969a(29) =8284346