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.

Previous Showing 11-20 of 20 results.

A126435 Primes of the form n^7-n-1.

Original entry on oeis.org

2097143, 1801088519, 21869999969, 42618442943, 78364164059, 137231006639, 194754273839, 435817657169, 678223072799, 1174711139783, 1727094849479, 3938980639103, 4398046511039, 4902227890559, 6722988818363, 19203908986079
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Comments

All terms end in 3 or 9. - Robert Israel, Jul 22 2019

Crossrefs

Programs

  • Maple
    map(t -> t^7-t-1, select(t -> isprime(t^7-t-1), [$1..10^4])); # Robert Israel, Jul 22 2019
  • Mathematica
    k = 7; a = {}; Do[If[PrimeQ[x^k - x - 1], AppendTo[a, x^k - x - 1]], {x, 1, 100}]; a
    Select[Table[n^7-n-1,{n,80}],PrimeQ] (* Harvey P. Dale, Jun 20 2020 *)

A126437 Primes of the form k^8-k-1.

Original entry on oeis.org

1679609, 5764793, 99999989, 4294967279, 282429536453, 377801998307, 5352009260441, 16815125390579, 39062499999949, 72301961339081, 83733937890569, 281474976710591, 513798374428571, 1113034787454899
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    k = 8; a = {}; Do[If[PrimeQ[x^k - x - 1], AppendTo[a, x^k - x - 1]], {x, 1, 100}]; a
    Select[Table[k^8-k-1,{k,80}],PrimeQ] (* Harvey P. Dale, Nov 06 2021 *)

A158295 Primes p such that p^3-p-+1 are twin primes.

Original entry on oeis.org

2, 11, 31, 41, 239, 521, 2309, 4099, 4409, 4441, 4651, 5009, 5039, 5261, 6481, 6871, 7129, 8609, 9391, 10259, 12841, 13759, 14519, 14879, 14939, 15569, 16871, 18451, 20369, 22441, 24049, 25841, 28151, 28279, 29429, 30181, 30631, 32089, 32299, 36781
Offset: 1

Views

Author

Keywords

Comments

Primes p such that p^3+p-+1 are twin primes, so far only one: 3. 3^3+3=30-+1 = primes.
Primes in the sequence A236524. Odd primes are congruent to either 1 mod 10 or 9 mod 10. - Derek Orr, Jan 27 2014

Examples

			2^3-2=6-+1 = 5,7 primes, 11^3-11-+1 = 1319,1321 primes...
		

Crossrefs

Programs

  • Mathematica
    lst={};Do[p=Prime[n];a=p^3-p;If[PrimeQ[a-1]&&PrimeQ[a+1],AppendTo[lst,p]],{n,8!}];lst
    Select[Prime[Range[3500]],And@@PrimeQ[#^3-#+{1,-1}]&] (* Harvey P. Dale, Jan 05 2013 *)
  • PARI
    s=[]; forprime(p=2, 40000, if(isprime(p^3-p-1) && isprime(p^3-p+1), s=concat(s, p))); s /* Colin Barker, Jan 28 2014 */
  • Python
    import sympy
    from sympy import isprime
    {print(p) for p in range(10**5) if isprime(p) and isprime(p**3-p-1) and isprime(p**3-p+1)} # Derek Orr, Jan 27 2014
    

A236524 Numbers n such that n^3 - n +/- 1 are twin primes.

Original entry on oeis.org

2, 4, 11, 14, 15, 21, 31, 35, 41, 45, 111, 130, 136, 140, 155, 176, 189, 221, 230, 239, 274, 316, 406, 414, 441, 465, 466, 504, 521, 561, 570, 580, 584, 591, 686, 689, 696, 759, 834, 836, 860, 869, 904, 960, 1026, 1159, 1379, 1539, 1614, 1625, 1660
Offset: 1

Views

Author

Derek Orr, Jan 27 2014

Keywords

Examples

			561^3 - 561 + 1 (176557921) and 561^3 - 561 - 1 (176557919) are twin primes. Thus, 561 is a member of this sequence.
		

Crossrefs

Intersection of A126421 and A236477.

Programs

  • Magma
    [n: n in [1..2000] | IsPrime(n^3-n-1) and IsPrime(n^3-n+1)]; // Vincenzo Librandi, Jan 30 2018
  • Mathematica
    Select[Range[2000], PrimeQ[#^3 - # - 1] && PrimeQ[#^3 - # + 1] &] (* Vincenzo Librandi, Jan 30 2018 *)
  • Python
    import sympy
    from sympy import isprime
    {print(n) for n in range(10**4) if isprime(n**3-n-1) and isprime(n**3-n+1)}
    

A126438 Primes of the form n^9-n-1.

Original entry on oeis.org

509, 262139, 10077689, 387420479, 68719476719, 118587876479, 1207269217769, 7625597484959, 10578455953379, 129961739795039, 327381934393919, 1628413597910399, 1953124999999949, 5416169448144839, 10077695999999939
Offset: 1

Views

Author

Artur Jasinski, Dec 26 2006

Keywords

Crossrefs

Programs

  • Mathematica
    k = 9; a = {}; Do[If[PrimeQ[x^k - x - 1], AppendTo[a, x^k - x - 1]], {x, 1, 100}]; a
    Select[Table[n^9-n-1,{n,100}],PrimeQ] (* Harvey P. Dale, Mar 09 2016 *)

A236168 Primes p such that p^3 - p - 1 is prime.

Original entry on oeis.org

2, 3, 11, 23, 29, 31, 41, 59, 71, 113, 151, 163, 191, 239, 241, 269, 359, 431, 433, 499, 503, 521, 541, 563, 661, 683, 701, 751, 773, 829, 883, 983, 1039, 1259, 1483, 1499, 1511, 1549, 1571, 1609, 1693, 1721, 1759, 1913
Offset: 1

Views

Author

Derek Orr, Jan 19 2014

Keywords

Comments

Primes in A126421.

Examples

			269 is prime and 269^3 - 269 - 1 is also prime. So, 269 is a member of this sequence.
		

Crossrefs

Cf. A126421.

Programs

  • Mathematica
    Select[Prime[Range[300]],PrimeQ[#^3-#-1]&] (* Harvey P. Dale, Nov 17 2014 *)
  • PARI
    s=[]; forprime(p=2, 2000, if(isprime(p^3-p-1), s=concat(s, p))); s \\ Colin Barker, Jan 20 2014
  • Python
    import sympy
    from sympy import isprime
    {print(p) for p in range(10**4) if isprime(p) and isprime(p**3-p-1)}
    

A236171 Numbers k such that k^2 - k - 1, k^3 - k - 1, and k^4 - k - 1 are all prime.

Original entry on oeis.org

4, 9, 11, 16, 55, 60, 71, 189, 361, 450, 469, 669, 1261, 1351, 1490, 1591, 2101, 2254, 2396, 2594, 3774, 3866, 4011, 5375, 5551, 5840, 6070, 7336, 7545, 7666, 7735, 8105, 8255, 9825, 10525, 11621, 12100, 13084, 13454
Offset: 1

Views

Author

Derek Orr, Jan 19 2014

Keywords

Examples

			3866^2 - 3866 - 1, 3866^3 - 3866 - 1, and 3866^4 - 3866 - 1 are all prime, so 3866 is a member of this sequence.
		

Crossrefs

Programs

  • Mathematica
    Select[Range[15000], And @@ PrimeQ[#^Range[2, 4] - # - 1] &] (* Amiram Eldar, Mar 21 2020 *)
  • PARI
    s=[]; for(n=1, 20000, if(isprime(n^2-n-1) && isprime(n^3-n-1) && isprime(n^4-n-1), s=concat(s, n))); s \\ Colin Barker, Jan 20 2014
  • Python
    import sympy
    from sympy import isprime
    {print(n) for n in range(10**5) if isprime(n**2-n-1) and isprime(n**3-n-1) and isprime(n**4-n-1)}
    

A236764 Numbers k such that k^3 +/- k +/- 1 are prime for all four possibilities.

Original entry on oeis.org

15, 21, 15375, 25164, 53361, 95190, 110685, 115140, 133701, 139425, 140430, 140844, 189336, 217686, 220650, 266916, 272469, 289341, 344880, 364665, 377805, 382221, 390270, 415779, 454905, 539700, 561186, 567645, 575799, 584430, 603651, 722484
Offset: 1

Views

Author

Derek Orr, Jan 30 2014

Keywords

Examples

			110685^3+110685+1 (1356020665779811), 110685^3+110685-1 (1356020665779809), 110685^3-110685+1 (1356020665558441) and 110685^3-110685-1 (1356020665558439) are all prime. Thus 110685 is a member of this sequence.
		

Crossrefs

Intersection of A126421, A236477, A049407, and A236475.

Programs

  • PARI
    for(n=1, 800000, if(isprime(n^3+n+1)&&isprime(n^3-n+1)&&isprime(n^3+n-1)&&isprime(n^3-n-1), print1(n, ","))) \\ Colin Barker, Jan 31 2014
  • Python
    import sympy
    from sympy import isprime
    {print(n) for n in range(10**6) if isprime(n**3+n+1) and isprime(n**3-n+1) and isprime(n**3+n-1) and isprime(n**3-n-1)}
    

A126439 Least prime of the form x^n-x-1.

Original entry on oeis.org

5, 5, 13, 29, 61, 2097143, 1679609, 509, 1021, 8589934583, 4093, 67108859, 16381, 470184984569, 4294967291, 2218611106740436979, 68719476731, 1350851717672992079, 1048573, 10460353199, 4194301, 20013311644049280264138724244295359, 16777213, 108347059433883722041830239, 20282409603651670423947251285999, 58149737003040059690390159, 72057594037927931, 536870909, 999999999999999999999999999989
Offset: 2

Views

Author

Artur Jasinski, Dec 26 2006, Jan 19 2007

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[k = 2; While[ ! PrimeQ[k^n -k - 1], k++ ]; AppendTo[a, k^n - k - 1], {n, 2, 30}]; a (*Artur Jasinski*)

A177089 Numbers n >= 0 such that n^3-n-1 is not prime.

Original entry on oeis.org

0, 1, 5, 6, 7, 10, 12, 13, 17, 19, 20, 22, 25, 26, 27, 28, 30, 32, 33, 34, 37, 39, 40, 42, 43, 44, 46, 47, 49, 50, 51, 52, 53, 54, 56, 57, 61, 62, 63, 65, 66, 67, 68, 72, 73, 74, 75, 77, 78, 79, 80, 82, 83, 84, 85, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 99, 100, 101, 102
Offset: 1

Views

Author

Vincenzo Librandi, Jun 05 2010

Keywords

Crossrefs

Cf. A126421.

Programs

  • Maple
    remove(n -> isprime(n^3-n-1), [$0..1000]); # Robert Israel, Jul 14 2017
  • PARI
    isok(n) = !isprime(n^3-n-1); \\ Michel Marcus, Jul 14 2017

Extensions

Checked by Jud McCranie, Jun 16 2010
0 and 1 added by R. J. Mathar, Jun 18 2010
Previous Showing 11-20 of 20 results.