M is the number of six-element subsets that can be chosen from the set of the first 15 positive integers so that at least three of the six numbers are consecutive.
Find M.

(In reply to 2 computer solutions; the second is probably right by Charlie)

Only 2 consecutive inequalities by 1 need to be found for there to be 3 consecutive numbers. The program's method 2 was looking for three consecutive inequalities by 1.

Posted by Charlie on 2016-02-09 16:29:47