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 21 results. Next

A132281 Noncomposites in A067200. Noncomposites (0, 1) and primes p such that A084380(p) = p^3 + 2 is prime.

Original entry on oeis.org

0, 1, 3, 5, 29, 71, 83, 113, 173, 263, 311, 419, 431, 491, 503, 509, 683, 701, 761, 773, 839, 911, 953, 1031, 1091, 1103, 1151, 1193, 1259, 1283, 1373, 1451, 1523, 1583, 1601, 1733, 1823, 1889, 1931, 2099, 2153, 2213, 2273, 2339, 2351, 2441, 2531, 2543
Offset: 1

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Author

Jonathan Vos Post, Aug 16 2007

Keywords

Comments

The corresponding near-cube primes are A132282. Analog of near-square primes. After a(1) = 0, 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 because 0^3 + 2 = 2 is prime and 0 is noncomposite.
a(2) = 1 because 1^3 + 2 = 5 is prime and 1 is noncomposite.
a(3) = 3 because 3^3 + 2 = 29 is prime and 3 is prime.
a(4) = 5 because 5^3 + 2 = 127 is prime and 5 is prime.
a(5) = 29 because 29^3 + 2 = 24391 is prime.
45 is not in the sequence because, although 45^3 + 2 = 91127 is prime, 45 is not prime.
63 is not in the sequence because, although 63^3 + 2 = 250049 is prime, 63 is not prime.
65 is not in the sequence because, although 65^3 + 2 = 274627 is prime, 65 is not prime.
a(6) = 71 because 71^3 + 2 = 357913 is prime.
a(7) = 83 because 83^3 + 2 = 571789 is prime.
a(8) = 113 because 113^3 + 2 = 1442899 is prime.
123 is not in the sequence because, although 123^3 + 2 = 1860869 is prime, 123 is not prime.
		

Crossrefs

Formula

{p in A000040 such that A067200(p) = A084380(p) = p^3 + 2 is in A000040}.
Union of {0,1} and A048637. - R. J. Mathar, Oct 18 2007

Extensions

More terms from R. J. Mathar, Oct 18 2007

A144953 Primes of form n^3 + 2.

Original entry on oeis.org

2, 3, 29, 127, 24391, 91127, 250049, 274627, 328511, 357913, 571789, 1157627, 1442899, 1860869, 2146691, 2924209, 3581579, 5000213, 5177719, 6751271, 9129331, 9938377, 10503461, 12326393, 14348909, 14706127, 15438251, 18191449
Offset: 1

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Author

Keywords

Comments

The Hardy-Littlewood conjecture K (p. 51) suggests that this sequence is infinite and gives an asymptotic estimate for the density of this sequence. - Charles R Greathouse IV, Jul 06 2010

Crossrefs

Cf. A067200.

Programs

  • Magma
    [a: n in [0..800] | IsPrime(a) where a is n^3+2]; // Vincenzo Librandi, Nov 30 2011
  • Maple
    N:= 10000: # number of terms desired
    R[1]:= 2: count:= 1:
    for n from 1 by 2 while count < N do
       p:= n^3+2;
       if isprime(p) then
         count:= count+1;
         R[count]:= p;
       end if
    end do:
    seq(R[n],n=1..N); # Robert Israel, Jan 29 2013
  • Mathematica
    lst={};Do[s=n^3;If[PrimeQ[p=s+2],AppendTo[lst,p]],{n,6!}];lst
    A144953={2};Do[If[PrimeQ[p=n^3+2],AppendTo[A144953,p]],{n,1,10^5,2}];A144953 (* Zak Seidov, Nov 05 2008 *)
    Select[Table[n^3+2,{n,0,7000}],PrimeQ] (* Vincenzo Librandi, Nov 30 2011 *)
  • PARI
    for(n=0,1e3,if(isprime(k=n^3+2),print1(k","))) \\ Charles R Greathouse IV, Jul 06 2010
    

Formula

a(n) = A067200(n)^3 + 2. - Zak Seidov, Sep 16 2013

Extensions

a(1)=2 from Zak Seidov, Nov 05 2008
Reference and index correction from Charles R Greathouse IV, Jul 06 2010

A125260 Numbers k such that k^5 + 4 is prime.

Original entry on oeis.org

1, 7, 9, 25, 39, 45, 73, 85, 99, 147, 163, 165, 169, 189, 213, 219, 223, 225, 249, 253, 259, 279, 333, 337, 385, 433, 457, 465, 469, 477, 499, 595, 639, 643, 655, 703, 709, 715, 729, 849, 853, 895, 969, 973, 979, 987, 1065, 1075, 1077, 1093, 1165, 1239, 1255
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), this sequence (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10), A125265 (j=11)...

Programs

A125259 Numbers k such that k^4 + 3 is prime.

Original entry on oeis.org

0, 2, 8, 16, 22, 26, 28, 34, 44, 62, 68, 76, 82, 92, 104, 110, 118, 128, 134, 166, 184, 202, 212, 266, 286, 296, 314, 328, 350, 356, 376, 406, 428, 436, 460, 470, 506, 520, 532, 562, 580, 638, 650, 652, 680, 692, 722, 734, 740, 778, 812, 820, 824, 862, 896, 908
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), this sequence (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10), A125265 (j=11)...

Programs

  • Mathematica
    Select[Range[0,1000],PrimeQ[#^4+3]&] (* Harvey P. Dale, Aug 02 2023 *)
  • PARI
    isok(n, k=4) = isprime(n^k + k - 1); \\ Michel Marcus, Oct 11 2013

A125262 Numbers k such that k^7 + 6 is prime.

Original entry on oeis.org

1, 13, 17, 23, 61, 73, 77, 101, 137, 215, 221, 283, 307, 317, 361, 431, 457, 473, 481, 641, 731, 767, 817, 881, 985, 1015, 1061, 1145, 1235, 1283, 1333, 1337, 1343, 1531, 1693, 1711, 1817, 1847, 1853, 1867, 1903, 1963, 2057, 2093, 2113, 2161, 2201, 2363
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259-A125265 (j=4..11).

Programs

A125265 Numbers k such that k^11 + 10 is prime.

Original entry on oeis.org

1, 7, 19, 21, 33, 69, 153, 157, 193, 253, 379, 391, 439, 543, 549, 559, 579, 609, 879, 937, 939, 993, 1063, 1083, 1107, 1119, 1191, 1209, 1267, 1281, 1287, 1333, 1537, 1617, 1797, 1819, 1923, 1971, 1987, 1989, 2041, 2061, 2073, 2101, 2103, 2343, 2373
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10).

Programs

A125261 Numbers k such that k^6 + 5 is prime.

Original entry on oeis.org

0, 18, 24, 114, 204, 216, 222, 246, 276, 312, 318, 372, 384, 426, 438, 468, 498, 582, 618, 654, 822, 888, 948, 984, 1182, 1188, 1272, 1278, 1284, 1374, 1446, 1536, 1674, 1782, 1788, 1794, 1806, 1812, 1896, 2034, 2058, 2088, 2124, 2154, 2232, 2238, 2376
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), this sequence(j=6), A125262 (j=7), A125263 (j=8), A125264 (j=10), A125265 (j=11)..

Programs

A125263 Numbers k such that k^8 + 7 is prime.

Original entry on oeis.org

0, 2, 4, 10, 66, 68, 86, 88, 134, 146, 200, 216, 250, 276, 306, 310, 410, 422, 472, 492, 506, 516, 538, 548, 550, 594, 638, 716, 746, 758, 862, 888, 942, 954, 964, 982, 992, 998, 1000, 1016, 1020, 1034, 1108, 1164, 1192, 1234, 1338, 1342, 1350, 1374, 1390
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), this sequence (j=8), A125264 (j=10), A125265 (j=11)...

Programs

A125264 Numbers k such that k^10 + 9 is prime.

Original entry on oeis.org

2, 8, 238, 310, 338, 442, 542, 688, 698, 872, 920, 1198, 1330, 1382, 1538, 1558, 1678, 1702, 1712, 1768, 1882, 2032, 2080, 2102, 2260, 2312, 2408, 2440, 2540, 2642, 3112, 3170, 3188, 3268, 3320, 3580, 3740, 3742, 3770, 3980, 4028, 4048, 4148, 4292, 4472
Offset: 1

Views

Author

Zak Seidov, Nov 26 2006

Keywords

Crossrefs

Other sequences of the type "Numbers k such that k^j + j - 1 is prime": A000040 (j=1), A005574 (j=2), A067200 (j=3), A125259 (j=4), A125260 (j=5), A125261 (j=6), A125262 (j=7), A125263 (j=8), this sequence (j=10), A125265 (j=11).

Programs

A159829 a(n) is the smallest natural number m such that n^3+m^3+1^3 is prime.

Original entry on oeis.org

1, 2, 1, 2, 1, 4, 15, 2, 3, 2, 11, 10, 9, 2, 7, 14, 5, 4, 9, 2, 15, 2, 7, 16, 15, 8, 13, 2, 1, 10, 3, 4, 15, 2, 11, 10, 9, 2, 7, 6, 13, 22, 5, 2, 1, 6, 29, 10, 29, 10, 3, 2, 11, 12, 3, 8, 3, 2, 19, 6, 15, 8, 1, 2, 1, 18, 5, 2, 1, 18, 1, 12, 17, 14, 15, 26, 7, 6, 3, 2, 19, 12, 1, 18, 3, 8, 15, 2, 11, 6
Offset: 1

Views

Author

Ulrich Krug (leuchtfeuer37(AT)gmx.de), Apr 23 2009

Keywords

Comments

a(2k-1) is odd, a(2k) is even.
Exponent 2: There are infinitely many primes of the forms n^2+m^2 and n^2+m^2+1^2.
Exponent k>2: Are there infinitely many primes of the forms n^k+m^k and n^k+m^k+1^k?

Examples

			2^3+2^3+1=17 = A000040(7); a(2)=2.
7^3+15^3+1=3719 = A000040(519); a(7)=15.
21^3+15^3+1=18523 = A000040(2122), a(21)=15.
		

References

  • L. E. Dickson, History of the Theory of Numbers, Vol, I: Divisibility and Primality, AMS Chelsea Publ., 1999.
  • A. Weil, Number theory: an approach through history, Birkhäuser 1984.
  • David Wells, Prime Numbers: The Most Mysterious Figures in Math. John Wiley and Sons. 2005.

Crossrefs

Cf. A067200 (when m=1).

Programs

  • Maple
    A159829 := proc(n) for m from 1 do if isprime(n^3+m^3+1) then RETURN(m) ; fi; od: end: seq(A159829(n),n=1..120) ; # R. J. Mathar, Apr 28 2009
  • Mathematica
    snn[n_]:=Module[{n3=n^3,m=1},While[!PrimeQ[n3+1+m^3],m++];m]; Array[ snn,100] (* Harvey P. Dale, Sep 04 2019 *)
  • PARI
    a(n) = my(m=1); while (!isprime(n^3+m^3+1^3), m++); m; \\ Michel Marcus, Nov 07 2023

Extensions

Corrected and extended by R. J. Mathar, Apr 28 2009
Showing 1-10 of 21 results. Next