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

arg 1: 6 == n  [length = m**n]  default=6

 n = 6  length = 64:
 0 000001 000011 000101 000111 001 001011 001101 001111 01 010111 011 011111 1
0000001000011000101000111001001011001101001111010101110110111111
 ct=64
