double factorial

短语

词形变化

double factorials 复数 double factorials

释义与例句

n.
  1. 1.

    For an odd integer, the result of multiplying all the odd integers from 1 to the given number; or for an even integer, the result of multiplying all the even integers from 2 to the given number; symbolised by a double exclamation mark (!!). For example, 9!! = 1 × 3 × 5 × 7 × 9 = 945.

    数学

词源

From double + factorial.

来源：wiktionary