The Excel PERMUT function returns the number of permutations (combinations where order is significant) of a given number of items. To use PERMUT, specify the total number of items and "number chosen", which represents the number of items in each...
The Excel FACTDOUBLE function returns the double factorial of a number. A double factorial is symbolized by two exclamation marks (!!).
Excel Formula Training
Formulas are the key to getting things done in Excel. In this accelerated training, you'll learn how to use formulas to manipulate text, work with dates and times, lookup values with VLOOKUP and INDEX & MATCH, count and sum with criteria, dynamically rank values, and create dynamic ranges. You'll also learn how to troubleshoot, trace errors, and fix problems. Instant access. See details here.