Data Structures, Algorithms, & Applications in C++
Chapter 7, Exercise 3

The mapping formula for general k is obtained using the same reasoning as used in Exercise 1. The formula is


map(i₁, i₂, ..., i_k) = i₁ u₂ u₃ ... u_k +  i₂ u₃ ... u_k + ... + i_k-2 u_k-1 u_k + i_k-1 u_k + i_k

Notice that


map(i₁, i₂, ..., i_k) = map(i₁, ... , i_k-1) * u_k + i_k

for k > 1.