Hexadecimal representation (base 16)
•12 stones
•12dec = C in hexadecimal representation (notation)
•123 stones
•123dec = 7B in hexadecimal representation (notation)
•
•123dec = 7*161 + 11*160        …8, 9, A, B, C, D, E, F
•             n
•Ndec = ∑ ai*16i
•                i=0