r=3, n=21, 11477 codewords.
Construction using the 3-identifying code with n=19 and 2846 codewords, which has
X2={7682 17182 28207 28447 40329 52767 59080 65702 67713 73609 74143 78246 79282 96431 108206 111031 128928 131604 131713 134857 136794 145208 155113 162771 165707 171849 181431 184748 190633 197546 217660 223186 234702 247839 248064 251826 256976 263531 266575 277242 279778 287149 301667 313747 323726 326808 343274 345210 348376 351408 351793 354423 376559 378627 381129 396738 399423 413317 418362 423493 427183 429609 432622 440153 442274 446632 458489 472436 487196 491226 502192 510625 517263 517712 520252 521285 521376} (77 elements)
Y2={74166 167497 522146 454828 158674 27679 349432 148030 311035 263650 487000 181391 215681 399727 7625 145240 26797 513097 311555 99470 325256 248090 417285 7779 234414 81150 133700 440753 358967 384533 487798} (31 elements):
11477 = 2846 x 4 + 31 x 3.