a(n) = Fibonacci(n)^4-1.

Terms

a(0) =0a(1) =0a(2) =15a(3) =80a(4) =624a(5) =4095a(6) =28560a(7) =194480a(8) =1336335a(9) =9150624a(10) =62742240a(11) =429981695a(12) =2947295520a(13) =20200652640a(14) =138458409999a(15) =949005240560