depth 1, size 1
depth 2, size 3
depth 3, size 7
depth 4, size 15
depth 5, size 31
depth 6, size 63
depth 7, size 127
depth 8, size 255
depth 9, size 511
depth 10, size 1023
depth 11, size 2047
depth 12, size 4095
depth 13, size 8191
depth 14, size 16383
depth 15, size 32767
depth 16, size 65535
depth 17, size 131071
depth 18, size 262143
depth 19, size 524287
depth 20, size 1048575
done.