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 1-6 of 6 results.

A086172 Numbers n such that n*prime(n)+1 is prime.

Original entry on oeis.org

1, 2, 4, 6, 24, 30, 36, 42, 72, 84, 98, 100, 116, 126, 128, 144, 162, 174, 206, 212, 228, 288, 312, 318, 324, 336, 350, 360, 406, 408, 416, 418, 452, 458, 466, 498, 510, 522, 528, 530, 536, 546, 548, 556, 604, 654, 660, 666, 682, 684, 690, 708, 710, 728, 738
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

See also A086173, A086174, A086175, A086176, A086177.

Links

Crossrefs

Cf. A086173, A086174, A086175, A086176, A086177.

Programs

  • Magma
    [n: n in [1..800] | IsPrime(n*NthPrime(n) + 1)]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[1000], PrimeQ[ # Prime[ # ]+1]&]
  • PARI
    is(n,p=prime(n))=isprime(n*p+1) \\ Charles R Greathouse IV, Feb 17 2017

A086173 Numbers k such that k*prime(k)-1 is prime.

Original entry on oeis.org

2, 8, 12, 14, 18, 30, 54, 66, 72, 80, 90, 94, 102, 110, 124, 144, 150, 160, 178, 184, 186, 198, 208, 210, 222, 224, 234, 250, 260, 264, 266, 280, 312, 336, 342, 370, 390, 400, 414, 432, 450, 462, 468, 470, 472, 476, 510, 564, 570, 596, 598, 600, 616, 652, 690
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

See also A086172, A086174, A086175, A086176, A086177.

Links

Crossrefs

Cf. A086172, A086174, A086175, A086176, A086177.

Programs

  • Magma
    [n: n in [1..800] | IsPrime(n*NthPrime(n) - 1)]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[1000], PrimeQ[ # Prime[ # ]-1]&]

A086174 Numbers n such that n*prime(n)+2 is a prime.

Original entry on oeis.org

3, 29, 33, 45, 65, 81, 91, 93, 95, 101, 103, 105, 109, 123, 153, 155, 189, 201, 225, 251, 253, 273, 283, 291, 305, 321, 363, 367, 371, 375, 387, 429, 431, 469, 475, 501, 515, 517, 525, 541, 567, 601, 613, 627, 633, 643, 669, 675, 701, 715, 717, 723, 729, 735
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

See also A086172, A086173, A086175, A086176, A086177.

Links

Crossrefs

Cf. A086172, A086173, A086175, A086176, A086177.

Programs

  • Magma
    [n: n in [1..800] | IsPrime(n*NthPrime(n) + 2)]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[1000], PrimeQ[ # Prime[ # ]+2]&]

A086176 Numbers n such that n*prime(n)+3 is prime.

Original entry on oeis.org

1, 4, 10, 20, 22, 28, 34, 38, 46, 56, 62, 92, 98, 112, 146, 148, 154, 166, 170, 176, 178, 200, 208, 254, 256, 260, 262, 266, 284, 340, 346, 352, 364, 394, 406, 412, 418, 460, 476, 500, 514, 524, 548, 550, 560, 574, 584, 586, 590, 610, 614, 620, 656, 664, 698
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

See also A086172, A086173, A086174, A086175, A086177.

Links

Crossrefs

Cf. A086172, A086173, A086174, A086175, A086177.

Programs

  • Magma
    [n: n in [1..800] | IsPrime(n*NthPrime(n) + 3)]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[1000], PrimeQ[ # Prime[ # ]+3]&]

A086177 Numbers n such that n*prime(n)-3 is prime.

Original entry on oeis.org

2, 8, 14, 34, 40, 46, 50, 80, 82, 88, 110, 116, 118, 130, 142, 200, 224, 226, 238, 256, 274, 278, 280, 286, 292, 302, 322, 328, 332, 350, 352, 362, 380, 398, 412, 430, 436, 464, 496, 544, 572, 586, 616, 620, 622, 634, 638, 646, 650, 662, 676, 688, 700, 734
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

See also A086172, A086173, A086174, A086175, A086176.

Links

Crossrefs

Cf. A086172, A086173, A086174, A086175, A086176.

Programs

  • Magma
    [n: n in [1..800] | IsPrime(n*NthPrime(n) - 3)]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[1000], PrimeQ[ # Prime[ # ]-3]&]

A085637 Numbers k such that k*prime(k) -+ 1 are twin primes.

Original entry on oeis.org

2, 30, 72, 144, 312, 336, 510, 690, 990, 1122, 1254, 1272, 1410, 2082, 2376, 2508, 2586, 2664, 2802, 3060, 3096, 3180, 3432, 3510, 3684, 4062, 4506, 5526, 5790, 6174, 7224, 8064, 8388, 9078, 9390, 9504, 10698, 10794, 10884, 10992, 11046, 11334
Offset: 1

Views

Author

Zak Seidov, Jul 11 2003

Keywords

Comments

Intersection of A086172 and A086173. See also A086174, A086175, A086176, A086177.

Examples

			k=30 is a term because 30*prime(30) +- 1 = 3390 +- 1 are twin primes.

Links

Crossrefs

Cf. A086172, A086173, A086174, A086175, A086176, A086177.

Programs

  • Magma
    [n: n in [1..11500] | IsPrime(n*NthPrime(n) - 1) and IsPrime(n*NthPrime(n) + 1) ]; // Vincenzo Librandi, Oct 05 2012
  • Mathematica
    Select[Range[15000], PrimeQ[ # Prime[ # ] - 1] && PrimeQ[ # Prime[ # ] + 1] &]
Select[Range[12000],AllTrue[#*Prime[#]+{1,-1},PrimeQ]&] (* Harvey P. Dale, Mar 21 2025 *)
Showing 1-6 of 6 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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