a(n) = floor(e^((n-1)/2)).

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =7a(6) =12a(7) =20a(8) =33a(9) =54a(10) =90a(11) =148a(12) =244a(13) =403a(14) =665a(15) =1096a(16) =1808a(17) =2980a(18) =4914a(19) =8103a(20) =13359a(21) =22026a(22) =36315a(23) =59874a(24) =98715a(25) =162754a(26) =268337a(27) =442413a(28) =729416a(29) =1202604