Question 884027
<pre>
We use the facts that {{{sum((1),i=1,matrix(1,2,"",n))=n}}} and {{{sum((i),i=1,matrix(1,2,"",n))=n(n+1)/2}}}


{{{sum((1+5i),i=1,13)}}}{{{""=""}}}{{{sum((1),i=1,13)+sum((5i),i=1,13)}}}{{{""=""}}}{{{sum((1),i=1,13)+5sum((i),i=1,13)}}}{{{""=""}}}{{{13+5*expr(13(13+1)/2)}}}{{{""=""}}}{{{468}}}

Edwin</pre>