a(n) = Fibonacci(4n+3) - 1, or Fibonacci(2n+2)*Lucas(2n+1).

A081009

a(n) = Fibonacci(4n+3) - 1, or Fibonacci(2n+2)*Lucas(2n+1).

Terms

    a(0) =1a(1) =12a(2) =88a(3) =609a(4) =4180a(5) =28656a(6) =196417a(7) =1346268a(8) =9227464a(9) =63245985a(10) =433494436a(11) =2971215072a(12) =20365011073a(13) =139583862444a(14) =956722026040

External references