In mathematics, An arithmetic progression is a sequence of numbers such that the difference of any two successive numbers of the sequence is a constant.
Arithmetic Progression = a1 + (n-1)* d
where:
a1 -> the first term in the series,
n -> last term in the series
d -> Common difference.
The nth term: an = am + (n-m)d
For instance, the first term a1 = 1, n = 3, common difference d = 2, Then the sequence is 1, 3, 5.
The 3th term is 5, Sum of first 3 terms is 9.