> -----Original Message-----
> From: maxima-bounces at math.utexas.edu
> [mailto:maxima-bounces at math.utexas.edu] On Behalf Of andre maute
> For beginners first:
>
> (a+b+<integer>+1)*(a+b+<integer>) => (a+b+<integer>)!
>
OK, so you are not changing factorial at all. You are changing the meaning
of "*".
Your rule is something like
<anything1> * (<noninteger_X>+ <integer_n1>)! * <anything2> *
(<noninteger_X> + <integer_n2>)!*<anything3>
with the side condition <integer_n1>= <integer_n2>+1
Then return
<anything1>*<anything2>*<anything3>*(<noninteger_X>+<integer_n1>)!
As it happens, this is done by factcomb(). Try it.
RJF