a(n) = Fibonacci(n-1) + Fibonacci(n+1) - (-1)^n.

Terms

a(0) =1a(1) =2a(2) =2a(3) =5a(4) =6a(5) =12a(6) =17a(7) =30a(8) =46a(9) =77a(10) =122a(11) =200a(12) =321a(13) =522a(14) =842a(15) =1365a(16) =2206a(17) =3572a(18) =5777a(19) =9350a(20) =15126a(21) =24477a(22) =39602a(23) =64080a(24) =103681a(25) =167762a(26) =271442a(27) =439205a(28) =710646a(29) =1149852