# Arithmetic progressions

How many arithmetic progressions of length 9 are there, such that the terms are integers from 1 to 70?

Details and assumptions

An Arithmetic Progression is a sequence of terms such that the difference between the consecutive terms is a constant. $$(1, 2, 3, 4), (1, 1, 1, 1), (4, 3, 2, 1)$$ are all valid arithmetic progressions of length 4.

×