a(n) = a(n-1)*3/2, if noninteger then rounded to the nearest even integer, with a(1) = 1.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =6a(5) =9a(6) =14a(7) =21a(8) =32a(9) =48a(10) =72a(11) =108a(12) =162a(13) =243a(14) =364a(15) =546a(16) =819a(17) =1228a(18) =1842a(19) =2763a(20) =4144a(21) =6216a(22) =9324a(23) =13986a(24) =20979a(25) =31468a(26) =47202a(27) =70803a(28) =106204a(29) =159306