Linear OA(5⁹¹, 4424, F₅, 20) (dual of [4424, 4333, 21]-code), using 4332 step VarÅ¡amov–Edel lengthening with (r_i) = (5, 2, 2, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 4 times 0, 1, 4 times 0, 1, 5 times 0, 1, 5 times 0, 1, 6 times 0, 1, 7 times 0, 1, 7 times 0, 1, 8 times 0, 1, 9 times 0, 1, 10 times 0, 1, 12 times 0, 1, 12 times 0, 1, 14 times 0, 1, 15 times 0, 1, 16 times 0, 1, 18 times 0, 1, 20 times 0, 1, 22 times 0, 1, 24 times 0, 1, 26 times 0, 1, 29 times 0, 1, 31 times 0, 1, 35 times 0, 1, 37 times 0, 1, 41 times 0, 1, 45 times 0, 1, 49 times 0, 1, 54 times 0, 1, 59 times 0, 1, 64 times 0, 1, 69 times 0, 1, 76 times 0, 1, 83 times 0, 1, 91 times 0, 1, 98 times 0, 1, 108 times 0, 1, 117 times 0, 1, 128 times 0, 1, 139 times 0, 1, 152 times 0, 1, 165 times 0, 1, 180 times 0, 1, 196 times 0, 1, 214 times 0, 1, 233 times 0, 1, 253 times 0, 1, 276 times 0, 1, 301 times 0, 1, 327 times 0, 1, 357 times 0) based on linear OA(5²⁰, 21, F₅, 20) (dual of [21, 1, 21]-code or 21-arc in PG(19,5)), using

• dual of repetition code with length 21 [i]