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

A081006

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

Terms

    a(0) =2a(1) =20a(2) =143a(3) =986a(4) =6764a(5) =46367a(6) =317810a(7) =2178308a(8) =14930351a(9) =102334154a(10) =701408732a(11) =4807526975a(12) =32951280098a(13) =225851433716

External references