r=4, n=20, 1710 codewords.

Construction using the 4-identifying code with n=19 and 835 codewords, which has

X₁={9754 13275 15710 16233 16380 18291 19229 20353 20798 21078 26841 27486 29715 32629 39231 40584 41526 44352 45137 47774 52249 52633 58751 59638 59688 60811 61141 61240 61426 62378 62520 62778 64252 68217 68382 68487 69866 71330 72435 72793 73403 80076 84516 86354 100826 100937 103445 105031 107410 110959 111168 121589 122947 130634 131218 136444 138088 138569 139476 139810 148966 150017 150365 152195 153078 157571 159654 166324 168028 174470 183930 184606 196495 196854 205071 206411 207569 210183 210503 210761 215733 217325 219577 220111 224758 226415 226695 227344 231133 232854 234571 235654 237080 240274 241446 244281 245571 246487 249277 249903 252342 253329 254443 258067 259119 265692 265747 269268 272616 273678 275859 279882 284401 285562 288679 291377 291473 291569 292390 293658 293726 294552 295676 296517 300956 304456 304781 306010 308152 308633 312795 315828 316428 320402 320449 320692 320944 322059 322426 326750 327277 328349 333453 336550 337310 342026 342600 344613 347577 350768 351277 352876 353802 354384 357474 358311 369239 369485 371999 374269 376983 381087 389955 392654 393426 396322 396327 399872 399896 399952 403911 404511 405106 410479 411182 411961 412451 413440 413486 415342 416872 421410 422150 424057 424572 426504 426776 433228 434472 435871 436260 436898 440850 440883 440886 441147 444018 447312 451523 453044 455545 456553 459218 459258 464527 468525 471125 473199 474386 477355 477375 477390 478540 478885 479797 480345 481467 481623 484791 487589 492506 495269 496283 497540 498073 498739 500361 501080 501871 505012 505021 507074 507727 508339 513099 513102 514546 516118 518335 519727 519735} (241 elements)

Y₁={65406 483375 395826 516755 496733 133590 350897 292278 339738 411490 236729 7001 451400 210563 375371 94290 378501 46744 281945 481357 78413 293480 429619 369310 63934 381402 191268 237447 300220 159425 500217 306634 45887 219708 105674 94297 252255 257402 406535 416668} (40 elements):

1710 = 835 x 2 + 40.