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 1-10 of 20 results. Next

A126424 Numbers k for which k^4-k-1 is prime.

Original entry on oeis.org

2, 4, 5, 6, 7, 9, 11, 13, 16, 20, 23, 26, 39, 40, 42, 44, 50, 53, 55, 57, 60, 61, 68, 71, 77, 79, 82, 92, 110, 111, 112, 123, 137, 139, 140, 147, 153, 154, 156, 169, 172, 174, 177, 183, 187, 189, 193, 198, 207, 214, 229, 230, 231, 239, 251, 258, 259, 272, 274, 279
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[x^4 - x - 1], AppendTo[a, x]], {x, 1, 1000}]; a

A116581 Primes of the form k^3 - k - 1.

Original entry on oeis.org

5, 23, 59, 503, 719, 1319, 2729, 3359, 4079, 5813, 9239, 12143, 13799, 24359, 29759, 42839, 46619, 54833, 68879, 91079, 110543, 166319, 195053, 205319, 215939, 262079, 328439, 342929, 357839, 438899, 531359, 635969, 941093, 1124759, 1259603, 1367519, 1442783
Offset: 1

Views

Author

Roger L. Bagula, Mar 22 2006

Keywords

Crossrefs

Programs

  • Magma
    [ a: n in [1..200] | IsPrime(a) where a is n^3-n-1 ]; // Vincenzo Librandi, Dec 07 2011
    
  • Mathematica
    Select[Table[n^3-n-1,{n,0,800}],PrimeQ] (* Vincenzo Librandi, Dec 07 2011 *)
  • Python
    from sympy import isprime
    def aupton(terms):
      k, alst = 2, []
      while len(alst) < terms:
        if isprime(k**3-k-1): alst.append(k**3-k-1)
        k += 1
      return alst
    print(aupton(37)) # Michael S. Branicky, May 23 2021

Formula

a(n) = A126420(A126421(n)). - Elmo R. Oliveira, Apr 20 2025

Extensions

Edited by N. J. A. Sloane, Jan 01 2007
More terms from Artur Jasinski, Jan 01 2007

A126422 Primes of the form k^4-k-1.

Original entry on oeis.org

13, 251, 619, 1289, 2393, 6551, 14629, 28547, 65519, 159979, 279817, 456949, 2313401, 2559959, 3111653, 3748051, 6249949, 7890427, 9150569, 10555943, 12959939, 13845779, 21381307, 25411609, 35152963, 38950001, 45212093
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[x^4 - x - 1], AppendTo[a, x^4 - x - 1]], {x, 1, 100}]; a
    Select[Table[n^4-n-1,{n,100}],PrimeQ] (* Harvey P. Dale, Aug 27 2013 *)

Formula

a(n) = A126423(A126424(n)). - Amiram Eldar, Mar 13 2020

Extensions

Definition corrected by Charles R Greathouse IV, Mar 11 2008

A126423 a(n) = n^4 - n - 1.

Original entry on oeis.org

-1, 13, 77, 251, 619, 1289, 2393, 4087, 6551, 9989, 14629, 20723, 28547, 38401, 50609, 65519, 83503, 104957, 130301, 159979, 194459, 234233, 279817, 331751, 390599, 456949, 531413, 614627, 707251, 809969, 923489, 1048543, 1185887, 1336301, 1500589, 1679579, 1874123, 2085097, 2313401, 2559959
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Magma
    [n^4-n-1: n in [1..40]]; // Vincenzo Librandi, Aug 30 2011
  • Mathematica
    a = {}; Do[AppendTo[a, x^4 - x - 1], {x, 1, 100}]; a

Formula

From Elmo R. Oliveira, Aug 29 2025: (Start)
G.f.: x*(-1 + 18*x + 2*x^2 + 6*x^3 - x^4)/(1-x)^5.
E.g.f.: 1 + (-1 + 7*x^2 + 6*x^3 + x^4)*exp(x).
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n > 5. (End)

A126426 a(n) = n^5 - n - 1.

Original entry on oeis.org

-1, 29, 239, 1019, 3119, 7769, 16799, 32759, 59039, 99989, 161039, 248819, 371279, 537809, 759359, 1048559, 1419839, 1889549, 2476079, 3199979, 4084079, 5153609, 6436319, 7962599, 9765599, 11881349, 14348879, 17210339, 20511119, 24299969, 28629119, 33554399, 39135359, 45435389
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Comments

Every number gives remainder 29 when divided by 30, remainder 9 when divided by 10, and remainder 4 when divided by 5.

Crossrefs

Programs

Formula

G.f.: x*(x^5-5*x^4+40*x^3+50*x^2+35*x-1)/(1-x)^6. - Colin Barker, Oct 07 2012

A126425 Primes of the form k^5-k-1.

Original entry on oeis.org

29, 239, 1019, 3119, 99989, 161039, 759359, 1048559, 1419839, 2476079, 3199979, 4084079, 14348879, 17210339, 24299969, 45435389, 60466139, 164916179, 254803919, 312499949, 550731719, 1934917559, 2373046799, 3707398349
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Comments

Every number give rest 29 when divided 30, rest 9 when divided 10, rest 4 when divided 5

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[x^5 - x - 1], AppendTo[a, x^5 - x - 1]], {x, 1, 100}]; a
    Select[Table[k^5-k-1,{k,90}],PrimeQ] (* Harvey P. Dale, Apr 21 2024 *)

Formula

a(n) = A126426(A126427(n)). - Amiram Eldar, Mar 13 2020

A126427 Numbers k for which k^5-k-1 is prime.

Original entry on oeis.org

2, 3, 4, 5, 10, 11, 15, 16, 17, 19, 20, 21, 27, 28, 30, 34, 36, 44, 48, 50, 56, 72, 75, 82, 84, 97, 101, 103, 105, 109, 113, 117, 130, 133, 141, 154, 157, 163, 177, 179, 188, 197, 204, 207, 218, 240, 248, 249, 250, 252, 262, 268, 281, 283, 285, 286, 291, 301, 305, 315
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[x^5 - x - 1], AppendTo[a, x]], {x, 1, 1000}]; a

A236477 Numbers k such that k^3 - k + 1 is prime.

Original entry on oeis.org

2, 4, 6, 7, 10, 11, 14, 15, 19, 21, 22, 25, 26, 31, 35, 39, 41, 42, 45, 50, 52, 54, 57, 62, 75, 77, 84, 85, 87, 90, 92, 95, 99, 101, 102, 106, 111, 116, 120, 125, 129, 130, 132, 134, 136, 139, 140, 141, 147, 155, 167, 169, 176, 189, 195, 202, 221, 230, 237
Offset: 1

Views

Author

Derek Orr, Jan 26 2014

Keywords

Examples

			26^3 - 26 + 1 = 17551 is prime. So 26 is a member of this sequence.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[250],PrimeQ[#^3-#+1]&] (* Harvey P. Dale, Dec 06 2017 *)
  • PARI
    s=[]; for(n=1, 500, if(isprime(n^3-n+1), s=concat(s, n))); s \\ Colin Barker, Jan 27 2014
  • Python
    import sympy
    from sympy import isprime
    {print(n) for n in range(10**3) if isprime(n**3-n+1)}
    

Extensions

More terms from Colin Barker, Jan 27 2014

A126434 Primes of the form k^6-k-1.

Original entry on oeis.org

61, 4091, 15619, 46649, 2985971, 16777199, 24137551, 63999979, 4750104199, 8303765579, 27680640569, 30840979399, 34296447191, 68719476671, 117648999929, 351298031531, 377149515539, 606355001251, 689869780961
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    k = 6; a = {}; Do[If[PrimeQ[x^k - x - 1], AppendTo[a, x^k - x - 1]], {x, 1, 100}]; a
    Select[Table[n^6-n-1,{n,200}],PrimeQ] (* Harvey P. Dale, Mar 28 2013 *)

A236475 Numbers k such that k^3 + k - 1 is prime.

Original entry on oeis.org

3, 4, 7, 10, 15, 16, 18, 21, 25, 27, 33, 36, 39, 43, 46, 51, 52, 55, 63, 73, 78, 81, 87, 93, 94, 96, 100, 103, 105, 109, 112, 115, 117, 120, 124, 127, 129, 135, 139, 145, 150, 151, 165, 166, 171, 178, 189, 192, 198, 199
Offset: 1

Views

Author

Derek Orr, Jan 26 2014

Keywords

Examples

			46^3 + 46 - 1 = 97381 is prime. So 46 is a member of this sequence.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[200],PrimeQ[#^3+#-1]&] (* Harvey P. Dale, Sep 02 2022 *)
  • PARI
    s=[]; for(n=1, 500, if(isprime(n^3+n-1), s=concat(s, n))); s \\ Colin Barker, Jan 27 2014
  • Python
    import sympy
    from sympy import isprime
    {print(n) for n in range(10**3) if isprime(n**3+n-1)}
    
Showing 1-10 of 20 results. Next