Let us define the set T = {1,2,3,...,700}. Now, S is a subset of T such that no two numbers in S differ by a difference of 2 or 5.

Determine the largest number of elements that S can have.

(In reply to Blindly crossing possible solution by Jer)

This agrees with my analysis in which the "keeping" or "discarding" pattern is 11001001100100...

Trying to get to the end and reverse this doesn't seem to allow a mesh with this forward sequence from the start and so it seems 300 is the highest possible.

Posted by Charlie on 2014-01-02 15:14:37