Wikipedia
Fibonorial
In mathematics, the Fibonorial , also called the Fibonacci factorial, where is a nonnegative integer, is defined as the product of the first positive Fibonacci numbers, i.e.
n! : = ∏F, n ≥ 0,where is the Fibonacci number, and gives the empty product (defined as the multiplicative identity, i.e. 1).
The Fibonorial is defined analogously to the factorial . The Fibonorial numbers are used in the definition of Fibonomial coefficients (or Fibonacci-binomial coefficients) similarly as the factorial numbers are used in the definition of binomial coefficients.