Product of numbers (a to b)
Multiply all integers from a to b. When starting from 1, this gives n! (factorial).
Fromto
Product of a range
1 × 2 × 3 × ... × n = n! (n factorial).
Factorial values
5! = 120. 10! = 3,628,800. 20! = 2.43 × 10¹⁸. Factorials grow extremely fast!
Applications
Counting permutations, combinatorics, probability, Taylor series coefficients.
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