Factorial.Double {Zseq}

Double Factorial numbers

Description

Under OEIS A000165 and A001147, a Double Factorial is the factorial of numbers with same parity. For example, if n=5, then n!!=5*3*1.

Usage

Factorial.Double(n, gmp = TRUE, odd = TRUE)

Arguments

n

the number of first n entries from the sequence.

gmp

a logical; TRUE to use large number representation, FALSE otherwise.

odd

a logical; TRUE for double factorial of odd numbers, FALSE for even numbers.

Value

a vector of length n containing first entries from the sequence.

See Also

Factorial

Examples

## generate first 10 double factorials
print(Factorial.Double(10))