@[Diogenes](/space/show?uid=53417)
`0!=1`，所以`C(0,0)=1`。
by Loner_Knowledge @ 2018-02-08 13:47:54
@[Diogenes](/space/show?uid=53417) wolframalpha.com
by Anguei @ 2018-02-08 13:50:51