a(n) = Fibonacci(2n+1) + n*2^(n-1).

Terms

a(0) =1a(1) =3a(2) =9a(3) =25a(4) =66a(5) =169a(6) =425a(7) =1058a(8) =2621a(9) =6485a(10) =16066a(11) =39921a(12) =99601a(13) =249666a(14) =628917a(15) =1592029a(16) =4048866a(17) =10341577a(18) =26517113a(19) =68226722a(20) =176065901a(21) =455514533a(22) =1181040514a(23) =3067684065a(24) =7980068641a(25) =20784441474a(26) =54188706405a(27) =141395801773