cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A176258 Numbers of the form 4k+1 with greatest prime divisor of the form 4m-1.

Original entry on oeis.org

9, 21, 33, 49, 57, 69, 77, 81, 93, 105, 121, 129, 133, 141, 161, 165, 177, 189, 201, 209, 213, 217, 237, 245, 249, 253, 285, 297, 301, 309, 321, 329, 341, 345, 361, 381, 385, 393, 413, 417, 437, 441, 453, 465, 469, 473, 489, 497, 501, 513, 517, 525, 529, 537, 553, 573
Offset: 1

Views

Author

Vladimir Shevelev, Apr 13 2010

Keywords

Comments

All terms of A107978 are in the sequence.

Links

Crossrefs

Cf. A176257, A176256, A176255, A107978, A002148, A002145, A016813, A004767.

Programs

  • Mathematica
    Select[4 Range@ 150 + 1, Mod[#, 4] == 3 &[FactorInteger[#][[-1, 1]]] &] (* Michael De Vlieger, Feb 07 2016 *)
  • PARI
    isok(n) = (n != 1) && ((n % 4) == 1) && ((vecmax(factor(n)[,1]) % 4) == 3); \\ Michel Marcus, Feb 07 2016

Extensions

Corrected and extended by Michel Marcus, Feb 07 2016

A176262 Numbers of the form 3k+1 with greatest prime divisor of the form 3m-1.

Original entry on oeis.org

4, 10, 16, 22, 25, 34, 40, 46, 55, 58, 64, 82, 85, 88, 94, 100, 106, 115, 118, 121, 136, 142, 145, 154, 160, 166, 178, 184, 187, 202, 205, 214, 220, 226, 232, 235, 238, 250, 253, 256, 262, 265, 274, 289, 295, 298, 319, 322, 328, 334, 340, 346, 352, 355, 358, 376
Offset: 1

Views

Author

Vladimir Shevelev, Apr 13 2010

Keywords

Comments

All numbers of the form 2p, where p==2(mod 3) is prime, are in the sequence.

Links

Crossrefs

Cf. A176258, A176257, A176256, A176255, A002148, A002145, A016813, A004767.

Programs

  • Mathematica
    Select[3 Range@ 120 + 1, Mod[#, 3] == 2 &[FactorInteger[#][[-1, 1]]] &] (* Michael De Vlieger, Feb 07 2016 *)
  • PARI
    isok(n) = ((n % 3) == 1) && (n != 1) && ((vecmax(factor(n)[,1]) % 3) == 2); \\ Michel Marcus, Feb 07 2016

Extensions

Corrected and extended by Michel Marcus, Feb 07 2016

A176274 Numbers of the form 3k-1 with greatest prime divisor of the form 3m+1.

Original entry on oeis.org

14, 26, 35, 38, 56, 62, 65, 74, 86, 95, 98, 104, 122, 134, 140, 143, 146, 152, 155, 158, 182, 185, 194, 206, 209, 215, 218, 224, 245, 248, 254, 260, 266, 278, 296, 302, 305, 314, 323, 326, 335, 338, 341, 344, 350, 362, 365, 380, 386, 392, 395, 398, 407, 416, 422, 434, 446
Offset: 1

Views

Author

Vladimir Shevelev, Apr 14 2010

Keywords

Comments

All numbers of the form 2p, where p==1(mod 3) is prime, are in the sequence.

Links

Crossrefs

Cf. A176262, A176258, A176257, A176256, A176255, A002148, A002145, A016813, A004767.

Programs

  • Mathematica
    Select[Range[500],Divisible[#+1,3]&&Divisible[FactorInteger[#] [[-1,1]]-1, 3]&] (* Harvey P. Dale, Jul 29 2019 *)
  • PARI
    isok(n) = ((n % 3) == 2) && ((vecmax(factor(n)[,1]) % 3) == 1); \\ Michel Marcus, Feb 08 2016

Extensions

More terms from Michel Marcus, Feb 08 2016

A176275 Numbers of the form 6k+1 with the least prime divisor of the form 6m-1.

Original entry on oeis.org

25, 55, 85, 115, 121, 145, 175, 187, 205, 235, 253, 265, 289, 295, 319, 325, 355, 385, 391, 415, 445, 451, 475, 493, 505, 517, 529, 535, 565, 583, 595, 625, 649, 655, 667, 685, 697, 715, 745, 775, 781, 799, 805, 835, 841, 865, 895, 901, 913, 925, 943, 955, 979, 985, 1003, 1015, 1045, 1075
Offset: 1

Views

Author

Vladimir Shevelev, Apr 14 2010

Keywords

Comments

All terms of A108166 are in the sequence.

Links

Crossrefs

Cf. A176274, A176262, A176256, A176257, A176258, A176255, A108166, A016969, A007528.

Programs

  • Mathematica
    Select[6*Range[200] + 1, IntegerQ[(FactorInteger[#][[1, 1]] + 1)/6] &] (* Harvey P. Dale, Sep 19 2018 *)
  • PARI
    isok(n) = ((n % 6) == 1) && (n != 1) && ((vecmin(factor(n)[,1]) % 6) == 5); \\ Michel Marcus, Feb 08 2016

Extensions

Corrected by R. J. Mathar, May 03 2013

A176278 Numbers of the form 6k-1 with the least prime divisor of the form 6m+1.

Original entry on oeis.org

77, 119, 161, 203, 221, 287, 299, 329, 371, 377, 413, 437, 497, 533, 539, 551, 581, 611, 623, 689, 707, 749, 767, 779, 791, 833, 893, 917, 923, 959, 1001, 1007, 1043, 1079, 1121, 1127, 1157, 1169, 1211, 1253, 1271, 1313, 1337, 1349, 1379, 1391, 1421, 1457
Offset: 1

Views

Author

Vladimir Shevelev, Apr 14 2010

Keywords

Comments

By definition, all terms are composite numbers.

Links

Crossrefs

Cf. A176275, A176274, A176262, A176258, A176257, A176256, A176255, A108166, A016969, A007528.

Programs

  • Mathematica
    Select[Range[11,2581,6],1==Mod[FactorInteger[ # ][[1,1]],6]&] (* Zak Seidov, Apr 14 2010 *)
  • PARI
    isok(n) = ((n % 6) == 5) && ((vecmin(factor(n)[,1]) % 6) == 1); \\ Michel Marcus, Feb 08 2016

Extensions

Corrected (erroneous 341 deleted) and extended by Zak Seidov, Apr 14 2010
Showing 1-5 of 5 results.

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