Re: Summation question
- To: mathgroup at smc.vnet.net
- Subject: [mg85706] Re: Summation question
- From: dh <dh at metrohm.ch>
- Date: Tue, 19 Feb 2008 07:07:21 -0500 (EST)
- References: <fpdu7v$qlq$1@smc.vnet.net>
Hi Robert,
applying Prime to a range of integers gives the prime indices (note that
by definition 1 is not but 2 is prime). Then we map f onto these primes
and finally use Total to get the sum:
Total[f /@ Prime@Range[6]]
hope this helps, Daniel
Robert Pigeon wrote:
> Good day all,
>
> I want to make a summation like this: Sum[f[i],{i, start,
> finish}]. What I want is that the sum be over a specific set like
> {1,3,5,7,11,13}. So the sum would be : f[1]+f[3]+f[5]+f[7]+f[11]+f[13]. The
> set I want to use is the primes. So, how do I use, if possible, Sum over a
> specific set ?
>
>
>
> Thanks,
>
>
>
> Robert
>
>
>
> Robert Pigeon
>
>