Half thrice the previous number, rounded down, plus 1, starting with 6.

Terms

a(0) =6a(1) =10a(2) =16a(3) =25a(4) =38a(5) =58a(6) =88a(7) =133a(8) =200a(9) =301a(10) =452a(11) =679a(12) =1019a(13) =1529a(14) =2294a(15) =3442a(16) =5164a(17) =7747a(18) =11621a(19) =17432a(20) =26149a(21) =39224a(22) =58837a(23) =88256a(24) =132385a(25) =198578a(26) =297868a(27) =446803a(28) =670205a(29) =1005308