CPM Homework Help : PC Problem 2-72

Express the given series using sigma notation, then evaluate the sums with your program or by hand.

$4+8+12+16+20$
Hint (a):
All of the numbers in the series are multiples of $4$ .

$1+2+4+8+16+32$
Hint (b):
The numbers in this series are all powers of $2$ .
It is easier to start with an index of $k=0$ instead of $k=1$ .

$2+4+6+8\ +\ ...\ +\ 200$
Hint (c):
All of the numbers in the series are multiples of $2$ .