Problem 45189. Double Factorial

        n(n-2)...(5)(3)(1),   n>0, odd
n!!  =  n(n-2)...(6)(4)(2),   n>0, even
        1                 ,   n = -1, or n = 0

Solution Comments

Problem Recent Solvers66

Suggested Problems

• Project Euler: Problem 6, Natural numbers, squares and sums.

  2326 Solvers

• Add two numbers

  1422 Solvers

• find the roots of a quadratic equation

  231 Solvers

• Counting down

  468 Solvers

• Convert from Fahrenheit to Celsius

  25177 Solvers

More from this Author92

• Modular multiplicative inverse

  21 Solvers

• Net Present Value of a Stream of Cash Flows

  36 Solvers

• Ordinary Annuity : Number of Payments (Present Value)

  20 Solvers

• Compound Interest: Present Value

  49 Solvers

• Find two triangular numbers whose sum is input.

  97 Solvers