An arithmetic progression is a sequence of numbers where the difference between consecutive terms is constant. The nth term of an arithmetic progression can be calculated as a+(n-1)d, where a is the first term, d is the common difference, and n is the term number. Some examples of arithmetic progressions include the sequence of odd numbers (with common difference of 2) and multiples of 3 (with common difference of 3). Formulas are also provided to calculate the nth term and sum of terms for an arithmetic progression.