Distances 6

#nexus

begin taxa;
  dimensions ntax=8;
  taxlabels taxon_1 taxon_2 taxon_3 taxon_4 taxon_5 taxon_6 taxon_7 taxon_8;
end;

[!
***********************************************
* Interleaved, lower-triangular, no diagonals *
***********************************************
]
begin distances;
  format nodiagonal interleave;
  matrix
    taxon_1
    taxon_2   1
    taxon_3   2  3
    taxon_4   4  5
    taxon_5   7  8
    taxon_6  11 12
    taxon_7  16 17
    taxon_8  22 23

    taxon_3
    taxon_4   6
    taxon_5   9 10
    taxon_6  13 14 15
    taxon_7  18 19 20
    taxon_8  24 25 26

    taxon_6
    taxon_7  21
    taxon_8  27 28;
end;