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 A251637 Square array read by antidiagonals containing in row n the multiples of prime(n) in A098550 in order of appearance. 6
 2, 3, 4, 15, 9, 8, 14, 5, 15, 14, 22, 35, 25, 6, 6, 39, 11, 7, 35, 12, 12, 51, 13, 33, 21, 10, 21, 16, 38, 17, 26, 55, 28, 20, 27, 10, 69, 19, 85, 65, 44, 91, 45, 39, 20, 87, 23, 95, 34, 91, 99, 49, 85, 33, 22, 62, 29, 115, 57, 68, 52, 77, 63, 55, 45, 26, 74 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS T(n,k) = A251715(n,k)*A000040(n); A251715(n,k) = T(n,k)/A000040(n); T(n,k) = A098550(A251716(n,k)); A251716(n,k) = A098551(T(n,k)); T(n,1) = A251618(n); for n > 4: T(n,2) = A000040(n); conjecture: A098550 is a permutation of the positive integers iff A001221(n) = number of rows containing n. A251541 = first column, and A251544 = third column for row numbers > 4. - Reinhard Zumkeller, Dec 16 2014 LINKS Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened EXAMPLE . n p | first 14 multiples of p = prime(n) in A098550, n = 1..25 . -------+------------------------------------------------------------- . 1 2 | 2 4 8 14 6 12 16 10 20 22 26 28 32 18 . 2 3 | 3 9 15 6 12 21 27 39 33 45 51 18 24 36 . 3 5 | 15 5 25 35 10 20 45 85 55 65 30 95 40 50 . 4 7 | 14 35 7 21 28 91 49 63 42 56 77 119 133 161 . 5 11 | 22 11 33 55 44 99 77 66 88 165 143 121 187 110 . 6 13 | 39 13 26 65 91 52 117 78 104 195 143 130 156 221 . 7 17 | 51 17 85 34 68 119 153 102 187 136 170 255 221 204 . 8 19 | 38 19 95 57 133 76 171 114 152 209 247 190 285 228 . 9 23 | 69 23 115 46 161 92 138 207 184 253 299 345 230 276 . 10 29 | 87 29 58 145 203 116 174 261 232 319 377 290 435 348 . 11 31 | 62 31 93 155 124 217 279 186 341 403 248 465 310 372 . 12 37 | 74 37 111 185 148 259 222 333 296 407 555 370 629 481 . 13 41 | 123 41 82 205 164 287 246 369 451 328 410 533 615 492 . 14 43 | 86 43 129 215 172 301 387 258 473 344 430 645 559 516 . 15 47 | 94 47 329 141 235 188 282 423 517 376 470 611 705 564 . 16 53 | 106 53 265 159 212 371 318 477 424 583 689 530 795 636 . 17 59 | 118 59 177 295 236 413 354 531 649 472 767 590 885 1003 . 18 61 | 122 61 427 183 305 244 366 549 671 488 793 610 915 732 . 19 67 | 201 67 335 134 268 469 603 402 536 737 871 670 1005 804 . 20 71 | 142 71 213 355 284 497 426 639 568 781 710 1065 923 852 . 21 73 | 146 73 365 219 292 511 438 657 584 803 730 949 1095 876 . 22 79 | 158 79 237 395 316 553 474 711 632 869 1027 790 1185 948 . 23 83 | 249 83 581 166 415 332 498 747 913 664 1079 830 1245 996 . 24 89 | 178 89 267 445 356 623 534 801 712 979 1157 890 1335 1068 . 25 97 | 291 97 679 194 485 388 582 873 1067 776 970 1261 1455 1164 . . --------------------------------------------------------------------- See also A251715 for a table with T(n,k)/p and A251716 for a table of indices of T(n,k) within A098550. MATHEMATICA rows = 25; (* f = A098550 *) Clear[f, row]; f[n_ /; n <= 3] := n; f[n_] := f[n] = Module[{k}, For[k=4, GCD[f[n-2], k] == 1 || GCD[f[n-1], k]>1 || MemberQ[Array[f, n-1], k], k++]; k]; row[n_] := row[n] = Module[{k, cnt}, Reap[For[k=1; cnt=0, cnt <= rows-n, k++, If[Divisible[f[k], Prime[n]], cnt++; Sow[f[k]]]]][[2, 1]]]; A251637 = Table[row[n-k+1][[k]], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Dec 17 2014 *) PROG (Haskell) when seen as table read by rows: a251637 n k = a251637_tabl !! (n-1) !! (k-1) a251637_row n= a251637_tabl !! (n-1) a251637_tabl = adias \$ map (\k -> filter ((== 0) . flip mod (fromInteger \$ a000040 k)) a098550_list) [1..] CROSSREFS Cf. A098550, A000040, A251618 (first column), A001221, A251715, A251716. Cf. A251541, A251544. Sequence in context: A204983 A249623 A367742 * A365436 A035047 A347335 Adjacent sequences: A251634 A251635 A251636 * A251638 A251639 A251640 KEYWORD nonn,tabl AUTHOR Reinhard Zumkeller, Dec 07 2014 STATUS approved

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Last modified June 21 07:08 EDT 2024. Contains 373540 sequences. (Running on oeis4.)