Are these numbers Madelung constants?
I don't know if this would be very helpful or not but as i had some free time on hand I got a list of Madelung Constant Values from the Internet 

In the list most of values were reported to 3-4 decimal places so I have Compared only the first decimal places as once the second decimal place was used none of the values matched. Maybe this would be a helpful start.

$$M_a$$ of ZnS (Wurtzite Hexagonal) is $10.7153$ (nearby the 12th and 18th entry in your table)

As Oscar Lanzi has commented $1.386$ is approximately $$2\log(2)$$ which is the Madelung constant for a one-dimensional line of alternating charges

As the question has been edited to add further details maybe the second one is a coincidence.

Only Nearby Matches So Far