a(n) = Fibonacci(4*n + 2).

Terms

a(0) =1a(1) =8a(2) =55a(3) =377a(4) =2584a(5) =17711a(6) =121393a(7) =832040a(8) =5702887a(9) =39088169a(10) =267914296a(11) =1836311903a(12) =12586269025a(13) =86267571272a(14) =591286729879