Alright, here's c145 with all basic elements shown for use in exploring this last post. I've included (-f na) (e na) (-f prime) (e prime) (-f Big N-1) and (e Big N) elements.
Found something interesting studying the Grid:
For c145, the (e,1) d value is 12
The (-f) d value is 13
13^2 - 12^2 = 25 = (an)
Don't know if it works for other c values yet.
knowing that d is always one unit bigger in -f, you could make the hypothesis that (d+1)^2 - d^2 = (an)
I'll run some more c values to check if this in yet another c145 fluke.