Mathematica > Mathematics and Algorithms > Discrete Mathematics > Combinatorial Functions > Factorial2 (!!)
Mathematica > Mathematics and Algorithms > Mathematical Functions > Integer Functions > Combinatorial Functions > Factorial2 (!!)
BUILT-IN MATHEMATICA SYMBOL

Factorial2

n!!
gives the double factorial of n.

DetailsDetails

  • Mathematical function, suitable for both symbolic and numerical manipulation.
  • .
  • n!! is a product of even numbers for n even, and odd numbers for n odd.
  • Factorial2 can be evaluated to arbitrary numerical precision.
  • Factorial2 automatically threads over lists.
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