Ceiling(3^n/n).

Terms

a(0) =3a(1) =5a(2) =9a(3) =21a(4) =49a(5) =122a(6) =313a(7) =821a(8) =2187a(9) =5905a(10) =16105a(11) =44287a(12) =122641a(13) =341641a(14) =956594a(15) =2690421a(16) =7596481a(17) =21523361a(18) =61171657a(19) =174339221a(20) =498112058a(21) =1426411801a(22) =4093181689a(23) =11767897354a(24) =33891544378a(25) =97764070321a(26) =282429536481