Originally Posted by
bobchiba regarding the sum,
I was shown in a previous thread a while ago that
Sn = n(a1 + an) / 2
so I ended up with 25( 1 + a20)
Why not 25(1+a50)?
Below is a brute force calculation of the sum:
Code:
>
>n=0:49;
>
>a=1+3*n;
>
>sum(a)
3725
>
RonL