| Ruud H.G. van Tol on Thu, 28 Aug 2025 14:26:38 +0200 |
[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]
| Re: PARI/GP wrong on 7!!+7+1 being not prime, or oeis.org/Mathematica? |
On 2025-08-28 14:16, Vincent Delecroix wrote:
The n!! notation is rather standard in combinatorics, see eg https://en.wikipedia.org/wiki/Double_factorial
Intriguing that it wasn't called half-factorial then. :) Or paritorial or such. -- Ruud