// output of ./demo/comb/debruijn-demo.cc:
// Description:
//% Generating De Bruijn sequences.

arg 1: 2 == m  [m-ary De Bruijn sequences]  default=2
arg 2: 4 == n  [length = m**n]  default=4

 n = 4  length = 16:
0 0001 0011 0101 111
