Re: Computing nCr how?
- To: mathgroup at smc.vnet.net
- Subject: [mg94892] Re: [mg94820] Computing nCr how?
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 29 Dec 2008 06:43:12 -0500 (EST)
- Reply-to: hanlonr at cox.net
expr = Binomial[n, r] // FunctionExpand
Gamma[n + 1]/(Gamma[r + 1]*
Gamma[n - r + 1])
expr /. Gamma[x_] :> (x - 1)!
n!/(r!*(n - r)!)
% == %% // FullSimplify
True
Table[Binomial[n, r], {n, 0, 5}, {r, 0, n}]
{{1},{1,1},{1,2,1},{1,3,3,1},{1,4,6,4,1},{1,5,10,10,5,1}}
Bob Hanlon
On Sat, Dec 27, 2008 at 9:47 AM , Affan wrote:
> Hi,
> I know this sounds simple but I cant find the function in mathematica
> to compute nCr (i.e. number of combination for n obj chosen in groups
> of r). Can anyone help?
>
> Thanks