Re: PARI/GP wrong on 7!!+7+1 being not prime, or oeis.org/Mathematica?

"Ruud H.G. van Tol" <[email protected]> Thu, 28 Aug 2025 14:26:32 +0200

Newsgroups	gmane.comp.mathematics.pari.user
Message-ID	<[email protected]>

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