Double Factorial of n Reference Values
Calculate n!! for non-negative integers up to 21 using the alternating-step factorial product.
On this page
Reference Value Index
This page lists 22 reference values for quick browsing and lookup.
All Reference Values
- 0 Integer n = 1 Double Factorial Value
- 1 Integer n = 1 Double Factorial Value
- 2 Integer n = 2 Double Factorial Value
- 3 Integer n = 3 Double Factorial Value
- 4 Integer n = 8 Double Factorial Value
- 5 Integer n = 15 Double Factorial Value
- 6 Integer n = 48 Double Factorial Value
- 7 Integer n = 105 Double Factorial Value
- 8 Integer n = 384 Double Factorial Value
- 9 Integer n = 945 Double Factorial Value
- 10 Integer n = 3,840 Double Factorial Value
- 11 Integer n = 10,395 Double Factorial Value
- 12 Integer n = 46,080 Double Factorial Value
- 13 Integer n = 135,135 Double Factorial Value
- 14 Integer n = 645,120 Double Factorial Value
- 15 Integer n = 2,027,025 Double Factorial Value
- 16 Integer n = 10,321,920 Double Factorial Value
- 17 Integer n = 34,459,425 Double Factorial Value
- 18 Integer n = 185,794,560 Double Factorial Value
- 19 Integer n = 654,729,075 Double Factorial Value
- 20 Integer n = 3,715,891,200 Double Factorial Value
- 21 Integer n = 13,749,310,575 Double Factorial Value
Reference Table
| n | n!! |
|---|---|
| 0 Integer n | 1 Double Factorial Value |
| 1 Integer n | 1 Double Factorial Value |
| 2 Integer n | 2 Double Factorial Value |
| 3 Integer n | 3 Double Factorial Value |
| 4 Integer n | 8 Double Factorial Value |
| 5 Integer n | 15 Double Factorial Value |
| 6 Integer n | 48 Double Factorial Value |
| 7 Integer n | 105 Double Factorial Value |
| 8 Integer n | 384 Double Factorial Value |
| 9 Integer n | 945 Double Factorial Value |
| 10 Integer n | 3,840 Double Factorial Value |
| 11 Integer n | 10,395 Double Factorial Value |
| 12 Integer n | 46,080 Double Factorial Value |
| 13 Integer n | 135,135 Double Factorial Value |
| 14 Integer n | 645,120 Double Factorial Value |
| 15 Integer n | 2,027,025 Double Factorial Value |
| 16 Integer n | 10,321,920 Double Factorial Value |
| 17 Integer n | 34,459,425 Double Factorial Value |
| 18 Integer n | 185,794,560 Double Factorial Value |
| 19 Integer n | 654,729,075 Double Factorial Value |
| 20 Integer n | 3,715,891,200 Double Factorial Value |
| 21 Integer n | 13,749,310,575 Double Factorial Value |
Frequently Asked Questions
Frequently asked questions for Double Factorial of n and its reference values.
What does the Double Factorial of n calculator do?
It helps with working with combinatorics identities, integrals, and closed-form sequences.
What formula does the Double Factorial of n calculator use?
n!! multiplies every other integer from n down to 1 or 2.
What inputs are valid?
n must be an integer from 0 to 21 for exact safe integer results in this calculator.
When would I use this?
working with combinatorics identities, integrals, and closed-form sequences
Methodology and Review
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