An arithmetic progression is a sequence of numbers in which the distance $($or difference$)$ between any two successive numbers if the same. This in the

sequence $1,3,5,7,$dots, the distance is $2$ while in the sequence $6,12,18,24,$dots, 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 $1+3+5+7+9=25.$