I need a maths formula for point distribution over a given length of material

I'm creating parametric models for manufacture. I intend to automate hole positions in manufacturing process for differing sizes of material.
I need a formula for hole distribution over a length of material given fixed distances from end of material and holes symmetrical over length at nearest 10 units spacing. Please see attached drawing for explanation. I only need the formula that can be put directly into the software or as excel formula.