An arithmetic progression is a sequence of numbers in which the distance (or difference) between any two successive numbers is the same. In the sequence 1, 3, 5, 7, ..., the distance is 2 while in the sequence 6, 12, 18, 24, ..., the distance is 6. Given the positive integer distance and the positive integer n, associate the variable sum with the sum of the elements of the arithmetic progression from 1 to n with distance distance. For example, if distance is 2 and n is 10, then sum would be associated with 25 because 1 3 5 7 9