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.

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A216976 Numbers k such that k^5+2 is prime.

Original entry on oeis.org

0, 1, 9, 11, 15, 27, 39, 51, 57, 105, 149, 179, 197, 219, 225, 231, 275, 281, 285, 299, 315, 317, 321, 335, 369, 389, 401, 405, 411, 419, 425, 491, 509, 545, 561, 587, 725, 741, 779, 789, 819, 855, 879, 909, 915, 977, 1007, 1019, 1059, 1115, 1145, 1161, 1199
Offset: 1

Views

Author

Michel Lagneau, Sep 21 2012

Keywords

Crossrefs

Programs

  • Maple
    select(t->isprime(t^5+2), [$0..10000]); # Robert Israel, Jan 01 2021
  • Mathematica
    lst={}; Do[If[PrimeQ[n^5+2], AppendTo[lst, n]], {n, 0, 10^3}]; lst
    Select[Range[0,1200],PrimeQ[#^5+2]&] (* Harvey P. Dale, Jan 30 2025 *)
  • PARI
    select(n->isprime(n^5+2),vector(2000,n,n-1)) /* Joerg Arndt, Sep 21 2012 */

A073573 Numbers n such that n^3 + 4 is prime.

Original entry on oeis.org

1, 3, 7, 9, 19, 25, 27, 45, 63, 69, 79, 85, 87, 99, 103, 109, 115, 117, 129, 133, 145, 169, 175, 183, 195, 207, 235, 277, 279, 283, 289, 295, 337, 343, 345, 355, 357, 363, 379, 469, 487, 495, 507, 519, 525, 529, 535, 537, 555, 559, 579, 645, 657, 663, 679, 703, 715, 717, 777, 783
Offset: 1

Views

Author

Zak Seidov, Sep 01 2002

Keywords

Crossrefs

Cf. A067200 (n^3+2 is prime).

Programs

Extensions

Corrected by Zak Seidov, Aug 31 2006
More terms from Vincenzo Librandi, Dec 16 2010

A132282 Near-cube primes: primes of the form p^3 + 2, where p is noncomposite.

Original entry on oeis.org

2, 3, 29, 127, 24391, 357913, 571789, 1442899, 5177719, 18191449, 30080233, 73560061, 80062993, 118370773, 127263529, 131872231, 318611989, 344472103, 440711083, 461889919, 590589721, 756058033, 865523179, 1095912793
Offset: 1

Views

Author

Jonathan Vos Post, Aug 16 2007

Keywords

Comments

The corresponding near-cube prime indices q are A132281. Analog of near-square primes. After a(1) = 2, all values must be odd. Numbers of the form n^2+2 for n=1, 2, ... are 3, 6, 11, 18, 27, 38, 51, 66, 83, 102, ... (A059100). These are prime for indices n = 1, 3, 9, 15, 21, 33, 39, 45, 57, 81, 99, ... (A067201), corresponding to the near-square primes 3, 11, 83, 227, 443, 1091, 1523, 2027, ... (A056899). Helfgott proves with minor conditions that: "Let f be a cubic polynomial. Then there are infinitely many primes p such that f(p) is squarefree." Note that 47^3 + 2 = 103825 = 5^2 * 4153 and similarly 97^3 + 2 is divisible by 5^2, but otherwise an infinite number of p^3+2 are squarefree.

Examples

			a(1) = 0^3 + 2 = 2 is prime and 0 is noncomposite.
a(2) = 1^3 + 2 = 3 is prime and 1 is noncomposite.
a(3) = 3^3 + 2 = 29 is prime and 3 is prime.
a(4) = 5^3 + 2 = 127 is prime and 5 is prime.
a(5) = 29^3 + 2 = 24391 is prime and 29 is prime.
45^3 + 2 = 91127 is prime, but not in this sequence because 45 is not prime.
63^3 + 2 = 250049 is prime, but not in this sequence because 63 is not prime.
a(6) = 71^3 + 2 = 357913 is prime.
a(7) = 83^3 + 2 = 571789 is prime.
a(8) = 113^3 + 2 = 1442899 is prime.
		

Crossrefs

Programs

  • Mathematica
    Join[{2, 5}, Select[Prime[Range[200]]^3 + 2, PrimeQ[ # ] &]] (* Stefan Steinerberger, Aug 17 2007 *)
  • PARI
    v=[2,3]; forprime(p=3, 1e4, if(isprime(t=p^3+2), v=concat(v, t))); t \\ Charles R Greathouse IV, Feb 14 2011

Formula

a(n) = A132281(n)^3 + 2. {p in A000040 such that for some q = 0, 1, or q in A000040, we have p = A067200(q) = A084380(q) = q^3 + 2 is in A000040}.
a(n) = A048636(n-2) for n >= 3. - Georg Fischer, Nov 03 2018

Extensions

More terms from Stefan Steinerberger, Aug 17 2007
a(2) corrected by Charles R Greathouse IV, Feb 14 2011

A216974 Numbers k such that k^4+2 is prime.

Original entry on oeis.org

0, 1, 3, 9, 15, 21, 45, 57, 63, 69, 87, 99, 129, 141, 279, 285, 333, 345, 453, 459, 465, 471, 513, 519, 627, 657, 669, 693, 729, 771, 777, 783, 795, 801, 807, 873, 909, 921, 933, 969, 987, 1011, 1023, 1047, 1119, 1155, 1257, 1299, 1323, 1407, 1419, 1437, 1485
Offset: 1

Views

Author

Michel Lagneau, Sep 21 2012

Keywords

Crossrefs

Cf. A067200, A067201, A182343 (associated primes).

Programs

  • Magma
    [n: n in [0..1500] | IsPrime(n^4+2)]; // Bruno Berselli, Sep 21 2012
  • Mathematica
    lst={}; Do[If[PrimeQ[n^4+2], AppendTo[lst, n]], {n, 0, 10^3}]; lst
    Select[Range[0, 1500], PrimeQ[#^4 + 2] &] (* Bruno Berselli, Sep 21 2012 *)
  • PARI
    select(n->isprime(n^4+2),vector(2000,n,n-1)) /* Joerg Arndt, Sep 21 2012 */
    

A216978 Numbers n such that n^6+2 is prime.

Original entry on oeis.org

0, 1, 39, 51, 81, 195, 213, 219, 231, 333, 351, 393, 417, 501, 531, 567, 657, 729, 747, 807, 945, 1005, 1059, 1161, 1173, 1185, 1191, 1203, 1281, 1335, 1371, 1467, 1479, 1563, 1587, 1647, 1653, 1749, 1761, 1821, 1845, 1875, 1929, 2373, 2379, 2421, 2529, 2595
Offset: 1

Views

Author

Michel Lagneau, Sep 21 2012

Keywords

Comments

Except for the first term, all terms must be odd numbers. - Harvey P. Dale, Sep 23 2012

Crossrefs

Programs

  • Mathematica
    lst={}; Do[If[PrimeQ[n^6+2], AppendTo[lst, n]], {n, 0, 3000}]; lst
    Join[{0},Select[Range[1,3001,2],PrimeQ[#^6+2]&]] (* Harvey P. Dale, Sep 23 2012 *)
  • PARI
    select(n->isprime(n^6+2),vector(2000,n,n-1)) /* Joerg Arndt, Sep 21 2012 */

A216980 Numbers n such that n^7+2 is prime.

Original entry on oeis.org

0, 1, 9, 21, 53, 63, 99, 123, 141, 155, 185, 213, 315, 363, 375, 449, 513, 521, 543, 555, 653, 669, 699, 731, 735, 759, 801, 843, 881, 975, 983, 995, 1031, 1095, 1115, 1131, 1149, 1161, 1221, 1253, 1395, 1413, 1451, 1473, 1491, 1571, 1599, 1625, 1659, 1733
Offset: 1

Views

Author

Michel Lagneau, Sep 21 2012

Keywords

Crossrefs

Programs

  • Mathematica
    lst={}; Do[If[PrimeQ[n^7+2], AppendTo[lst, n]], {n, 0, 10^3}]; lst
    Select[Range[0,2000],PrimeQ[#^7+2]&] (* Harvey P. Dale, Mar 29 2016 *)
  • PARI
    select(n->isprime(n^7+2),vector(2000,n,n-1)) /* Joerg Arndt, Sep 21 2012 */

A073574 Numbers n such that n^3 + 6 is prime.

Original entry on oeis.org

1, 5, 7, 13, 17, 41, 73, 77, 101, 103, 133, 143, 145, 161, 173, 181, 187, 251, 271, 283, 293, 313, 325, 391, 395, 425, 461, 497, 503, 511, 523, 581, 593, 595, 647, 671, 703, 733, 745, 803, 805, 815, 833, 847, 853, 875, 941, 965, 973, 997, 1001, 1021, 1085, 1091, 1097, 1111, 1141, 1183
Offset: 1

Views

Author

Zak Seidov, Sep 01 2002

Keywords

Crossrefs

Cf. A067200 (n^3+2 is prime).

Programs

  • Magma
    [n: n in [0..1500]|IsPrime(n^3+6)]; // Vincenzo Librandi, Dec 16 2010
    
  • Mathematica
    Select[ Range[ 950 ], PrimeQ[ #^3+6 ] & ]
    Select[Range[1,1201,2],PrimeQ[#^3+6]&] (* Because all terms must be odd, there is no need to test even numbers *) (* Harvey P. Dale, Oct 03 2018 *)
  • PARI
    is(n)=isprime(n^3+6) \\ Charles R Greathouse IV, Jun 12 2017

Extensions

More terms from Vincenzo Librandi, Dec 16 2010

A269346 Perfect cubes that are not the difference of two primes.

Original entry on oeis.org

343, 729, 1331, 2197, 3375, 4913, 6859, 9261, 12167, 15625, 19683, 29791, 35937, 42875, 50653, 59319, 68921, 79507, 103823, 117649, 132651, 148877, 166375, 185193, 205379, 226981, 300763, 389017, 421875, 456533, 493039, 531441, 614125, 658503, 704969
Offset: 1

Views

Author

Waldemar Puszkarz, Feb 24 2016

Keywords

Comments

An even number can be the difference of two primes, but an odd one can only be if an odd number m is such that m+2 is prime. Since a(n) is odd and such that a(n)+2 is composite, a(n) cannot be such a difference.
The cubes of this property are also the cubes in A269345.
It is still an open conjecture that every even number is the difference of 2 primes. On the other hand, a computer test shows that all even cubes <= 10^21 can be written as the difference of 2 primes. The computer program generating the sequence needs an additional part to test for even cubes besides checking that for odd m^3, m^3+2 is composite. - Chai Wah Wu, Mar 03 2016

Examples

			For n=1, 343 = 7^3 and 345 = 343+2 is a composite, so 343 is a term.
		

Crossrefs

Cf. A000578 (the cubes), A067200 (cube roots of terms that complement this sequence), A269345 (supersequence).

Programs

  • Magma
    [n^3: n in [1..150 by 2] | not IsPrime(n^3+2)]; // Vincenzo Librandi, Feb 28 2016
  • Mathematica
    Select[Range[1,125,2]^3, !PrimeQ[#+2]&]
    Select[Range[125]^3, !PrimeQ[#+2]&&OddQ[#]&]
    Select[Select[Range[2000000], OddQ[#]&& !PrimeQ[#]&& !PrimeQ[#+2]&], IntegerQ[CubeRoot[#]]&]
  • PARI
    for(n=1, 125, n%2==1&&!isprime(n^3+2)&&print1(n^3, ", "))
    

A329727 Numbers k such that k^3 +- 2 and k +- 2 are prime.

Original entry on oeis.org

129, 1491, 1875, 2709, 5655, 6969, 10335, 14325, 14421, 17319, 26559, 35109, 37509, 43719, 50229, 52629, 101871, 102795, 104325, 105501, 120429, 127599, 132699, 136395, 137829, 157521, 172425, 173685, 179481, 186189, 191829, 211371, 219681, 221199, 229215, 234195
Offset: 1

Views

Author

K. D. Bajpai, Nov 19 2019

Keywords

Comments

All terms in this sequence are divisible by 3.

Examples

			a(1) = 129:
  129^3 + 2 = 2146691;
  129^3 - 2 = 2146687;
  129   + 2 =     131;
  129   - 2 =     127; all four results are prime.
a(2) = 1491:
  1491^3 + 2 = 3314613773;
  1491^3 - 2 = 3314613769;
  1491   + 2 =       1493;
  1491   - 2 =       1489; all four results are prime.
		

Crossrefs

Intersection of A038599, A067200, and A087679.

Programs

  • Magma
    [k:k in [1..250000]|forall{m:m in [-2,2]|IsPrime(k+m) and IsPrime(k^3+m)}]; // Marius A. Burtea, Nov 20 2019
    
  • Mathematica
    Select[Range[500000], PrimeQ[#^3 + 2] && PrimeQ[#^3 - 2] && PrimeQ[# + 2] && PrimeQ[# - 2] &]
  • PARI
    isok(k) = isprime(k-2) && isprime(k+2) && isprime(k^3-2) && isprime(k^3+2); \\ Michel Marcus, Nov 24 2019
    
  • PARI
    list(lim)=my(v=List(),p=127,k); forprime(q=131,lim+2,if(q-p==4 && isprime((k=p+2)^3-2) && isprime(k^3+2), listput(v,k)); p=q); Vec(v) \\ Charles R Greathouse IV, May 06 2020

A073598 Numbers n such that n^3 + 5 is prime.

Original entry on oeis.org

2, 12, 14, 24, 26, 38, 42, 48, 56, 66, 78, 86, 92, 104, 116, 126, 138, 146, 164, 186, 192, 194, 198, 224, 242, 264, 276, 296, 324, 332, 386, 438, 488, 494, 498, 518, 524, 566, 576, 582, 588, 594, 596, 632, 684, 696, 698, 714, 716, 722, 728, 738, 758, 762, 806
Offset: 1

Views

Author

Zak Seidov, Sep 01 2002

Keywords

Comments

For n^3+2 prime see A067200. For n^3+3 prime see A049441.

Crossrefs

Programs

  • Magma
    [n: n in [1..900] | IsPrime(n^3 + 5)]; // Vincenzo Librandi, Sep 30 2012
    
  • Mathematica
    Select[ Range[ 950 ], PrimeQ[ #^3+5 ] & ]
  • PARI
    is(n)=isprime(n^3+5) \\ Charles R Greathouse IV, Jun 12 2017
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