A005922 a(1)=1; a(n) = n!*Fibonacci(n+2), n > 1.

1, 6, 30, 192, 1560, 15120, 171360, 2217600, 32296320, 522547200, 9300614400, 180583603200, 3798482688000, 86044973414400, 2088355965696000, 54064489070592000, 1487129136869376000, 43312058119249920000

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Comments

From solution to a difference equation.

References

• N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Links

• Vincenzo Librandi, Table of n, a(n) for n = 1..200
• P. R. J. Asveld & N. J. A. Sloane, Correspondence, 1987
• P. R. J. Asveld, Another family of Fibonacci-like sequences, Fib. Quart., 25 (1987), 361-364.

Crossrefs

Cf. A005921, A078700.

Programs

Magma

[1] cat [Factorial(n)*Fibonacci(n+2): n in [2..20]]; // Vincenzo Librandi, Jul 10 2012

Mathematica

Join[{1},Table[n!Fibonacci[n+2],{n,2,20}]] (* Harvey P. Dale, May 26 2024 *)

PARI

a(n)=if(n>1, n!*fibonacci(n+2), 1) \\ Charles R Greathouse IV, Jun 30 2017

Extensions

More terms and better description from Vladeta Jovovic, Jan 23 2005