r=5, n=20, 663 codewords.

Construction using the 5-identifying code with n=19 and 326 codewords, which has

X₁={27295 32440 34030 72402 82154 83370 86526 88505 94930 95882 116692 118724 120796 128603 134214 142236 143019 145498 147063 165018 181588 191949 210357 214527 221493 223979 225622 226623 228669 242104 245245 258906 262456 265258 271128 272468 274143 295216 311330 312668 324512 330041 336184 343344 348668 349632 366688 379552 379649 381044 382699 390156 420002 425365 426068 427361 434532 449090 460995 461154 462763 480905 483322 486134 490226 495812 497976} (67 elements)

Y₁={346531 489983 165316 381224 163547 250140 350922 207280 264722 415128 429534} (11 elements):

663 = 326 x 2 + 11.