Jones–Nachtsheim definitive screening design: 2k+1 foldover pairs + center (optionally +2 extra centers → 2k+3). Levels ∈ {−1, 0, +1}.
Optional
Jones–Nachtsheim definitive screening design: 2k+1 foldover pairs + center (optionally +2 extra centers → 2k+3). Levels ∈ {−1, 0, +1}.