summation in pari gp

Adrian · 2022-08-12, 07:51

Is there any command to evaluate in PARI GP such sum: $\sum\limits_{\substack{2\leq d\leq n \\ (d, n)=1}}\frac{a\left(n\right)}{d}$?

In other words: how to add to command

sum(d=2, n, \frac{a(n)}{d})

condition from second line $(d,n)=1$) (or more such conditions)

LaurV · 2022-08-12, 09:48

you mean this?

Code:

gp > sum(d=1,20,if(d%2==0&&d%3==0,1./d,0),0)
%1 = 0.30555555555555555555555555555555555556
gp > 1./6+1/12+1/18
%2 = 0.30555555555555555555555555555555555556
gp >

Pari is a programing language, how you combine the stuff is up to you

(p.s. I also edited your post and fixed your formula)

2022-08-12, 07:51	#1
Adrian Aug 2022 1₁₀ Posts	summation in pari gp Is there any command to evaluate in PARI GP such sum: \(\sum\limits_{\substack{2\leq d\leq n \\ (d, n)=1}}\frac{a\left(n\right)}{d}\)? In other words: how to add to command sum(d=2, n, \frac{a(n)}{d}) condition from second line $(d,n)=1$) (or more such conditions) Last fiddled with by LaurV on 2022-08-12 at 09:40 Reason: fixed the formula

2022-08-12, 09:48	#2
LaurV Romulan Interpreter "name field" Jun 2011 Thailand 3×23×149 Posts	you mean this? Code: gp > sum(d=1,20,if(d%2==0&&d%3==0,1./d,0),0) %1 = 0.30555555555555555555555555555555555556 gp > 1./6+1/12+1/18 %2 = 0.30555555555555555555555555555555555556 gp > Pari is a programing language, how you combine the stuff is up to you (p.s. I also edited your post and fixed your formula)

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