Re: sum over i+j+k==n
- To: mathgroup at smc.vnet.net
- Subject: [mg84441] Re: [mg84423] sum over i+j+k==n
- From: Bob Hanlon <hanlonr at cox.net>
- Date: Mon, 24 Dec 2007 04:49:01 -0500 (EST)
- Reply-to: hanlonr at cox.net
n = 4;
Sum[f[i, j, n - i - j], {i, 0, n}, {j, 0, n - i}]
f(0,0,4)+f(0,1,3)+f(0,2,2)+f(0,3,1)+f(0,4,0)+f(1,0,3)+f(1,1,2)+
f(1,2,1)+f(1,3,0)+f(2,0,2)+f(2,1,1)+f(2,2,0)+f(3,0,1)+f(3,1,0)+f(4,0,0)
Bob Hanlon
]
---- Jack Kennedy <jack at realmode.com> wrote:
> Hi All,
> I often find myself needing to sum over triples
> (or other tuples) like i,j,k where i+j+k=n. Is there
> a convenient way to write this in Mathematica?
> Thanks,
> Jack
>
> (version 5.1)
>