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>

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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

>

>

```

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