Given the sequence in the table below, determine the sigma notation of the sum for term 4 through term 15.
n an
1 5
2 −10
3 20
a. the summation of 5 times negative 2 to the n minus 1 power, from n equals 4 to 15
b. the summation of 5 times negative 2 n, from n equals 1 to 15
c. the summation of 5 times negative 2 to the n plus 1 power, from n equals 4 to 15
d. the summation of 5 times negative 2 times n to the n plus 1 power, from n equals 1 to 15