1/4+2/5+1/2+...+11/14
If you consider the 
as 
, then it goes
where the numerators go 1,2,3,4,...,11 which is n going
from 1 to 11. Then the denominators go 4,5,6,7,...,14
and each denominator is always 3 more than the numerator.
So the denominators are the numerators, n, plus 3, so the
summation is
Edwin
