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 1-3 of 3 results.

A129213 Numbers m such that 7!*m-/+1 are twin primes.

Original entry on oeis.org

7, 11, 13, 20, 22, 37, 41, 46, 47, 48, 56, 57, 90, 102, 103, 135, 142, 164, 190, 216, 217, 230, 241, 254, 279, 290, 318, 332, 333, 340, 362, 385, 405, 407, 420, 428, 431, 470, 473, 476, 486, 494, 499, 518, 526, 531, 553, 554, 565, 571, 584, 587, 592, 605, 609
Offset: 1

Views

Author

Zak Seidov, Apr 03 2007

Keywords

Links

Crossrefs

Cf. A014574 (Average of twin prime pairs), A127545 (Multiples of 7 such that n -/+ 1 are twin primes).
Numbers m such that (N!*m -/+ 1) are twin primes: A129214 (N=8), A129215 (N=9), A129216 (N=10).

Programs

  • Mathematica
    s={};Do[m=5040k;If[PrimeQ[m-1]&&PrimeQ[m+1],AppendTo[s,k]],{k,1000}];s

Formula

7!*a(n) are terms in A014574.

A129215 Numbers m such that 9!*m -+ 1 are twin primes.

Original entry on oeis.org

3, 11, 22, 38, 52, 69, 125, 140, 154, 167, 169, 185, 198, 200, 205, 239, 299, 308, 335, 368, 376, 390, 405, 421, 482, 509, 574, 597, 610, 663, 684, 700, 701, 720, 763, 792, 795, 798, 840, 843, 855, 898, 907, 921, 954, 957
Offset: 1

Views

Author

Zak Seidov, Apr 03 2007

Keywords

Links

Crossrefs

Cf. A014574 (average of twin prime pairs), A127545 (multiples of 7 in A014574), A137877.
Numbers m such that (N!*m -+ 1) are twin primes: A129213 (N=7), A129214 (N=8), A129216 (N=10).

Programs

  • Magma
    [m:m in [1..1000]| IsPrime(Factorial(9)*m+1) and IsPrime(Factorial(9)*m-1)]; // Marius A. Burtea, Dec 29 2019
  • Mathematica
    s={};Do[m=362880k;If[PrimeQ[m-1]&&PrimeQ[m+1],AppendTo[s,k]],{k,1000}];s
With[{c=9!},Select[Range[1000],And@@PrimeQ[c*#+{1,-1}]&]] (* Harvey P. Dale, Aug 27 2013 *)

Formula

9!*a(n) are terms in A014574.

A129216 Numbers m such that 10!*m-/+1 are twin primes.

Original entry on oeis.org

14, 20, 39, 61, 70, 72, 84, 107, 136, 235, 279, 281, 282, 319, 324, 360, 369, 422, 451, 513, 539, 547, 594, 598, 611, 647, 673, 684, 744, 783, 809, 823, 851, 911, 918, 919, 935, 957, 968
Offset: 1

Views

Author

Zak Seidov, Apr 04 2007

Keywords

Links

Crossrefs

Cf. A014574 (Average of twin prime pairs), A127545 (Multiples of 7 such that n -/+ 1 are twin primes).
Numbers m such that (N!*m -/+ 1) are twin primes: A129213 (N=7), A129214 (N=8), A129215 (N=9).

Programs

  • Mathematica
    s={};Do[m=3628800k;If[PrimeQ[m-1]&&PrimeQ[m+1],AppendTo[s,k]],{k,1000}];s
With[{c=10!},Select[Range[1000],And@@PrimeQ[c #+{1,-1}]&]] (* Harvey P. Dale, Jun 23 2012 *)

Formula

10!*a(n) are terms in A014574.
Showing 1-3 of 3 results.

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

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