We have

6

∑ 5 + 6n

n = 1

When

n = 1 we have 11

n = 2 we have 17

And we are summing these through n = 6 ( = 41 )

Note : This is not unique.....there are other ways, as well, depending upon our starting value for n

Another possibility is

5

∑ 11 + 6n

n = 0

Hope that helps !!!!