Pettifor' sequence , even with the limited dataset and methods used by the time of its formulation in 1980, improves substantially with respect to Z, and performs well afterwards, achieving comparable results to Glawe et al.' sequences, which further improve Pettifor's but not substantially. Oganov et al.' sequence shows slightly better performance than Z, although far below Pettifor or Glawe et al.'s. Our optimised sequences substantially improve L relative to these baselines for each of the years considered, which validates their use as suitable representations of the periodic system.