28  reverse
    1 T       0    2    0    1
    2 C       1    3    0    2
    3 T       2    4    0    3
    4 C       3    5    0    4
    5 T       4    6    0    5
    6 G       5    7    0    6
    7 G       6    8    0    7
    8 A       7    9    0    8
    9 C       8   10    0    9
   10 T       9   11    0   10
   11 T      10   12    0   11
   12 T      11   13    0   12
   13 G      12   14    0   13
   14 T      13   15    0   14
   15 A      14   16   25   15
   16 C      15   17   24   16
   17 T      16   18   23   17
   18 A      17   19    0   18
   19 G      18   20    0   19
   20 G      19   21    0   20
   21 T      20   22    0   21
   22 T      21   23    0   22
   23 G      22   24   17   23
   24 G      23   25   16   24
   25 T      24   26   15   25
   26 T      25   27    0   26
   27 T      26   28    0   27
   28 G      27    0    0   28