Template talk:Factorial!
120 {{subst:#ifexpr:{{subst:#expr:5-1=1|{{{2}}}| {{subst:#ifexpr:3
{{subst:#ifexpr:5=1|1|{{subst:factorial!|{{subst:#expr:5-1}}{{subst:pipe}}{{subst:#expr:1*5}}}}}} {{subst:#ifexpr:4|5=1|{{{2}}}|{{subst:factorial!|{{subst:#expr:4|5-1}}{{subst:pipe}}{{subst:#expr:{{{2}}}*4|5}}}}}} 120
{{subst:factorial!|10|1}} gives
3628800
in two saves.
{{subst:factorial|10}} gives
3628800
in one save.