Linear OA(7⁵³, 397, F₇, 19) (dual of [397, 344, 20]-code), using 343 step VarÅ¡amov–Edel lengthening with (r_i) = (4, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 4 times 0, 1, 4 times 0, 1, 5 times 0, 1, 6 times 0, 1, 6 times 0, 1, 8 times 0, 1, 9 times 0, 1, 10 times 0, 1, 11 times 0, 1, 13 times 0, 1, 15 times 0, 1, 17 times 0, 1, 19 times 0, 1, 21 times 0, 1, 24 times 0, 1, 26 times 0, 1, 30 times 0, 1, 34 times 0, 1, 38 times 0) based on linear OA(7¹⁹, 20, F₇, 19) (dual of [20, 1, 20]-code or 20-arc in PG(18,7)), using

• dual of repetition code with length 20 [i]