Floor(r*a(n-1)) + floor(r*a(n-2)), where r = 5/3, a(0) = 1, a(1) = 1.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =9a(5) =21a(6) =50a(7) =118a(8) =279a(9) =661a(10) =1566a(11) =3711a(12) =8795a(13) =20843a(14) =49396a(15) =117064a(16) =277432a(17) =657492a(18) =1558206a(19) =3692830a(20) =8751726a(21) =20740926a(22) =49154420a(23) =116492243a(24) =276077771a(25) =654283356a(26) =1550601878a(27) =3674808723a(28) =8709017668a(29) =20639710651