Re: Summation question

*To*: mathgroup at smc.vnet.net*Subject*: [mg85743] Re: [mg85664] Summation question*From*: Sseziwa Mukasa <mukasa at jeol.com>*Date*: Wed, 20 Feb 2008 07:06:10 -0500 (EST)*References*: <200802190647.BAA27190@smc.vnet.net>

On Feb 19, 2008, at 1:47 AM, 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 ? One way is to map the sum indices to the set elements eg: Sum[f[Prime[i]],{i,start,finish}] but this may present problems if the sum is over an infinite range. Regards, Sseziwa

**Follow-Ups**:**Re: Re: Summation question***From:*Andrzej Kozlowski <akoz@mimuw.edu.pl>

**References**:**Summation question***From:*Robert Pigeon <robert.pigeon@videotron.ca>