Hi Cesar,
There is nothing wrong with using 1,2,3,4,..., or whatever, for
seeds. Your seed sequence does not need to appear random.
For programs taking a seed, it is common to start with some
modestly large number (e.g. 12345) and just increment from
there.
The main reason programs take seeds is so results can be
reproduced given the same seed, if desired. Some programs
use a fixed seed by default (as 3dkmeans claims to do), some
do not (so repeated calls without a seed would be different).
- rick