r=2, n=21, 50342 codewords.
Construction using the 2-identifying code with n=19 and 12458 codewords, which has
X2={190 206 675 1650 1752 6862 8772 10703 11534 13303 14640 14964 16068 16541 18931 20437 22219 23172 25277 26195 26618 28573 29111 29711 33708 34320 36904 37194 42721 44017 45841 48392 48415 48960 49418 50934 50997 51465 53246 54156 62196 62960 64380 64930 69721 69997 70444 70620 74837 76948 79754 81731 83150 84120 84276 84521 84813 87297 92085 92245 92294 92336 94023 95026 95750 95858 96227 96577 98650 99142 101826 102430 103136 108343 110084 110596 111473 112323 116275 116692 117212 118614 120922 121076 121537 122051 123906 124349 127090 128861 131633 132246 135138 136471 137982 139098 139365 139486 142373 144379 145045 146208 148136 148336 151666 153589 157661 160550 161931 163548 163715 165138 165257 167545 169301 170745 171394 171982 172351 172885 173266 173504 173745 175295 176221 178875 181248 183532 184247 186030 186919 187370 187408 187692 188967 190187 191077 191410 192168 192247 194041 194209 197390 199575 200895 201165 201627 202727 202989 205632 207596 208228 213197 213392 213532 213752 216492 218175 222502 223110 224355 224385 224588 231058 232895 234634 236666 240034 240527 244660 248614 248643 253119 254477 254526 254535 255300 257426 257611 258296 261820 264169 264674 265287 270738 271299 272344 273818 275660 278221 279678 280541 282356 284983 287655 288527 289694 296266 297696 297809 298409 301201 302177 302299 309897 311074 311715 312622 313201 316741 322348 323864 327284 327981 328394 328741 329074 330359 331874 333805 334002 335993 336736 342070 348009 349373 349584 351956 355195 356629 357307 358153 359816 362078 363206 364389 372061 372257 373952 375834 382738 387130 388226 388331 390497 392728 393071 393228 393453 394116 394758 397130 398607 405113 407392 407466 408348 408592 410440 411669 412970 414995 416864 416967 416984 417525 419005 419157 423113 423954 426105 429052 429994 433310 433547 434774 439371 440957 441354 442512 445240 450571 454614 456094 457183 459131 459758 461842 462195 462450 464203 464827 468004 468520 468702 469723 470495 471148 473061 474021 474382 474684 477933 479989 482978 483097 484053 487855 488404 488917 490680 493624 495392 495725 502049 502567 505257 507009 509966 514150 514808 516120 517183 517384 521661 523752} (326 elements)
Y2={64116 165010 33098 116535 26589 397290 460147 433290 200909 488149 490920 26226 191015 470751 488637 69933 278220 518200 464869 286452 503585 79811 84841 224580 183724 222 254492 48398 190177 426093 176469 218303 92308 250616 398615 256579 256434 393732 297969 202683 261800 107012 459598 147600 468832 59390 121052 199567 162699 137934 333938 484644 138256 506788 470145 175799 199405 453416 494374 271770 416960 39648 45937 488383 18588 423253 376346 58368 91069 408124 194040 102214 18388 29687 173441 330434 34456 253018 689 101571 264153 25871 301193 49058 95014 406859 514126 441977 314666 461906 491273 177083 188362 410464 456159 23436 140945 340057 269511 73813 287619 86130 139840 171641 264691 14624 233399 341930 222726 169090 388235 86337 382354 382309 141349 481922 425180 55133 355178 90389 84388 233494 330323 394277 11719 49911 22091 521513 124213 518408 364333 473197 149525 188070 308672 378462 28615 451593 499798 517143 410825 453590 187073 329256 70600 27548 82062 173887 35937 137178 62744 161780 311106 12328 34217 283063 370742 474142 52505 494524 388975 503135 40091 280318 296355 224352 41902 290834 149162 313173} (170 elements):
50342 = 12458 x 4 + 170 x 3.