Floor((e/2)^n).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =4a(6) =6a(7) =8a(8) =11a(9) =15a(10) =21a(11) =29a(12) =39a(13) =54a(14) =73a(15) =99a(16) =135a(17) =184a(18) =250a(19) =340a(20) =462a(21) =628a(22) =854a(23) =1161a(24) =1578a(25) =2145a(26) =2916a(27) =3964a(28) =5387a(29) =7322