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 38 results. Next

A075725 Duplicate of A049407.

Original entry on oeis.org

1, 2, 3, 5, 6, 8, 9, 12, 15, 17, 18, 21, 29, 30, 32, 39, 41, 42, 44, 48, 53, 54, 56, 60, 69
Offset: 1

Views

Author

Keywords

A002384 Numbers m such that m^2 + m + 1 is prime.

Original entry on oeis.org

1, 2, 3, 5, 6, 8, 12, 14, 15, 17, 20, 21, 24, 27, 33, 38, 41, 50, 54, 57, 59, 62, 66, 69, 71, 75, 77, 78, 80, 89, 90, 99, 101, 105, 110, 111, 117, 119, 131, 138, 141, 143, 147, 150, 153, 155, 161, 162, 164, 167, 168, 173, 176, 188, 189, 192, 194, 203, 206, 209, 215
Offset: 1

Views

Author

Keywords

Comments

A002383 lists the corresponding primes. - Bernard Schott, Dec 22 2012
This is also the list of bases where 111 represents a prime number. - Christian N. K. Anderson, Mar 28 2013
If d>1 divides m^2 + m + 1, then m + k*d is not in the sequence, for all k>=1. - Gionata Neri, Mar 04 2017

References

  • A. J. C. Cunningham, Binomial Factorisations, Vols. 1-9, Hodgson, London, 1923-1929; see Vol. 1, pp. 245-259.
  • D. H. Lehmer, Guide to Tables in the Theory of Numbers. Bulletin No. 105, National Research Council, Washington, DC, 1941, p. 46.
  • L. Poletti, Le serie dei numeri primi appartenente alle due forme quadratiche (A) n^2+n+1 e (B) n^2+n-1 per l'intervallo compreso entro 121 milioni, e cioè per tutti i valori di n fino a 11000, Atti della Reale Accademia Nazionale dei Lincei, Memorie della Classe di Scienze Fisiche, Matematiche e Naturali, s. 6, v. 3 (1929), pages 193-218.
  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

Formula

a(n) = (A088503(n) - 1)/2. - Ray Chandler

Extensions

Extended by Ray Chandler, Sep 07 2005

A244376 Numbers k such that 1 + k + k^3 + k^5 + k^7 + k^9 + k^11 is prime.

Original entry on oeis.org

1, 2, 10, 40, 47, 55, 62, 121, 137, 152, 167, 201, 233, 278, 290, 293, 313, 333, 370, 382, 430, 452, 460, 506, 546, 555, 613, 625, 642, 675, 705, 711, 752, 767, 793, 797, 831, 835, 837, 872, 878, 891, 906, 917, 923, 978, 985, 1005, 1012, 1017, 1018, 1021
Offset: 1

Views

Author

Vincenzo Librandi, Jun 27 2014

Keywords

Crossrefs

Cf. A127936.
Cf. numbers n such that 1+n+n^3 + ... + n^k, with k odd: A006093 (k=1), A049407 (k=3), A124154 (k=5), A124150 (k=7), A124163 (k=9), this sequence (k=11), A124164 (k=13), A244377 (k=15), A244378 (k=17), A124178 (k=19), A244379 (k=21), A124181 (k=23), A244380 (k=25), A124185 (k=27), A244383 (k=29), A124186 (k=31), A244384 (k=33), A124187 (k=35), A244385 (k=37), A124189 (k=39), A244386 (k=41), A124200 (k=43), A244387 (k=45), A124205 (k=47), A244388 (k=49), A124206 (k=51), A244389 (k=53), A124207 (k=55), A244390 (k=57), A124208 (k=59), A244391 (k=61), A124209 (k=63).

Programs

  • Magma
    [n: n in [0..1500] | IsPrime(s) where s is 1+&+[n^i: i in [1..11 by 2]]];
    
  • Mathematica
    Select[Range[4000], PrimeQ[Total[#^Range[1, 11, 2]] + 1] &]
  • PARI
    isok(n) = isprime(1 + n + n^3 + n^5 + n^7 + n^9 + n^11); \\ Michel Marcus, Jun 27 2014
    
  • Sage
    i,n = var('i,n')
    [n for n in (1..2000) if is_prime(1+(n^(2*i+1)).sum(i,0,5))] # Bruno Berselli, Jun 27 2014

A124178 Numbers n such that 1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17 + n^19 is prime.

Original entry on oeis.org

1, 3, 6, 33, 36, 61, 70, 99, 168, 229, 267, 268, 321, 325, 337, 366, 387, 448, 456, 457, 498, 513, 532, 546, 591, 621, 624, 637, 835, 858, 910, 927, 961, 981, 1045, 1125, 1213, 1237, 1242, 1257, 1341, 1357, 1437, 1458, 1461, 1462, 1482, 1491, 1572, 1579, 1581
Offset: 1

Views

Author

Artur Jasinski, Dec 13 2006

Keywords

Crossrefs

Cf. A049407, similar sequences listed in A244376.

Programs

  • Magma
    [n: n in [0..2000] | IsPrime(1 +n +n^3 +n^5 +n^7 +n^9 +n^11 +n^13 +n^15 +n^17 +n^19)]; // Vincenzo Librandi, Nov 12 2010
    
  • Magma
    [n: n in [0..2000] | IsPrime(s) where s is 1+&+[n^i: i in [1..19 by 2]]]; // Vincenzo Librandi, Jun 28 2014
    
  • Mathematica
    Do[If[PrimeQ[1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17 + n^19], Print[n]], {n, 1, 1000}]
    Select[Range[3000], PrimeQ[Total[#^Range[1, 19, 2]] + 1] &] (* Vincenzo Librandi, Jun 28 2014 *)
  • PARI
    is(n)=n==1 || isprime((n^21-n)/(n^2-1)+1) \\ Charles R Greathouse IV, Jul 02 2013
    
  • Sage
    i,n = var('i,n')
    [n for n in (1..2000) if is_prime(1+(n^(2*i+1)).sum(i,0,9))] # Bruno Berselli, Jun 28 2014

A124181 Numbers n such that 1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17 + n^19 + n^21 + n^23 is prime.

Original entry on oeis.org

1, 3, 69, 86, 104, 110, 138, 146, 210, 238, 247, 260, 264, 269, 316, 436, 572, 600, 621, 654, 666, 715, 737, 740, 744, 754, 779, 1056, 1156, 1159, 1216, 1218, 1221, 1343, 1419, 1434, 1442, 1524, 1580, 1603, 1676, 1680, 1731, 1742, 1804, 1952, 1956, 1985
Offset: 1

Views

Author

Artur Jasinski, Dec 13 2006

Keywords

Crossrefs

Cf. A049407, similar sequences listed in A244376.

Programs

  • Magma
    [n: n in [0..2000] | IsPrime(s) where s is 1+&+[n^i: i in [1..23 by 2]]]; // Vincenzo Librandi, Jun 28 2014
  • Mathematica
    Do[If[PrimeQ[1 + n + n^3 + n^5 + n^7 + n^9 + n^11 + n^13 + n^15 + n^17 + n^19 + n^21 + n^23], Print[n]], {n, 1, 1400}]
    Select[Range[3000], PrimeQ[Total[#^Range[1, 23, 2]] + 1] &] (* Vincenzo Librandi, Jun 28 2014 *)
  • PARI
    is(n)=n==1 || isprime((n^25-n)/(n^2-1)+1) \\ Charles R Greathouse IV, Jul 02 2013
    
  • Sage
    i,n = var('i,n')
    [n for n in (1..2000) if is_prime(1+(n^(2*i+1)).sum(i,0,11))] # Bruno Berselli, Jun 27 2014
    

Formula

1 together with numbers n such that (n^25-n)/(n^2-1) + 1 is prime. - Charles R Greathouse IV, Jul 02 2013

A049408 Numbers k such that k^4 + k + 1 is prime.

Original entry on oeis.org

1, 2, 5, 6, 9, 11, 12, 14, 24, 26, 32, 36, 44, 47, 60, 69, 72, 74, 77, 89, 90, 102, 107, 119, 126, 131, 146, 147, 159, 162, 170, 171, 186, 191, 197, 204, 206, 219, 239, 240, 252, 266, 284, 285, 290, 296, 300, 324, 347, 351, 362, 384, 426, 437, 459, 465, 470
Offset: 1

Views

Author

Keywords

Comments

For s = 5,8,11,14,17,20,..., n_s = 1 + n + n^s is always composite for any n > 1. Also for n=1, n_s=3 is a prime for any s. Here we consider the case s=4.

Examples

			26 is a term because at s=4, n=26, n_s = 1 + n + n^s = 457003 is a prime.
		

Crossrefs

Programs

  • Magma
    [n: n in [0..1000] | IsPrime(s) where s is 1+n+n^4]; // Vincenzo Librandi, Jul 28 2014
  • Mathematica
    Select[Range[1000], PrimeQ[1 + # + #^4] &] (* Vincenzo Librandi, Jul 28 2014 *)
  • PARI
    for(n=1, 1000, if(isprime(1+n+n^4), print1(n",")))
    

A126908 Numbers k such that 1 + k^2 + k^4 + k^6 + k^7 is prime.

Original entry on oeis.org

1, 4, 13, 15, 24, 30, 37, 40, 55, 93, 138, 139, 148, 153, 154, 159, 160, 165, 184, 195, 204, 223, 258, 303, 355, 360, 373, 459, 472, 475, 510, 519, 534, 577, 594, 607, 615, 627, 658, 672, 688, 723, 735, 739, 795, 805, 807, 817, 819, 820, 847, 874, 879, 904
Offset: 1

Views

Author

Artur Jasinski, Dec 31 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[1 + n^2 + n^4 + n^6 + n^7], AppendTo[a, n]], {n, 1, 1400}]; a
    Select[Range[1000],PrimeQ[1+#^2+#^4+#^6+#^7]&] (* Harvey P. Dale, Jan 15 2016 *)
  • PARI
    is(n)=isprime(1+n^2+n^4+n^6+n^7) \\ Charles R Greathouse IV, Feb 17 2017

A126916 Numbers n such that 1 + n^2 + n^4 + n^6 + n^8 + n^10 + n^12 + n^14 + n^16 + n^18 + n^20 + n^22 + n^23 is prime.

Original entry on oeis.org

1, 2, 11, 23, 47, 64, 77, 80, 103, 251, 290, 321, 331, 335, 375, 382, 387, 403, 507, 568, 590, 594, 649, 801, 805, 828, 830, 840, 847, 854, 905, 925, 926, 959, 982, 986, 1034, 1086, 1094, 1102, 1122, 1129, 1147, 1160, 1391
Offset: 1

Views

Author

Artur Jasinski, Dec 31 2006

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[1 + n^2 + n^4 + n^6 + n^8 + n^10 + n^12 + n^14 + n^16 + n^18 + n^20 + n^22 + n^23], AppendTo[a, n]], {n, 1, 1400}]; a
    Select[Range[1400],PrimeQ[Total[#^Range[2,22,2]]+1+#^23]&] (* Harvey P. Dale, Oct 04 2018 *)
  • PARI
    is(n)=isprime(1+n^2+n^4+n^6+n^8+n^10+n^12+n^14+n^16+n^18+n^20+n^22+n^23) \\ Charles R Greathouse IV, Feb 17 2017

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

A075723 Numbers n such that 1 + n + n^6 is a prime.

Original entry on oeis.org

1, 2, 3, 6, 8, 15, 17, 29, 30, 32, 45, 48, 59, 72, 74, 80, 87, 128, 141, 153, 155, 156, 158, 176, 182, 191, 197, 210, 216, 230, 273, 284, 293, 305, 314, 356, 366, 380, 384, 399, 402, 407, 408, 410, 413, 420, 435, 443, 447, 450, 473, 479, 497
Offset: 1

Views

Author

Zak Seidov, Oct 03 2002

Keywords

Comments

For s = 5,8,11,14,17,20,..., n_s=1+n+n^s is always composite for any n>1. Also at n=1, n_s=3 is a prime for any s. So it is interesting to consider only the cases of s != 5,8,11,14,17,20,... and n>1. Here I consider the case s=6 and find several first n's making n_s a prime (or a probable prime).

Examples

			15 is OK because at s=6, n=15, n_s = 1 + n + n^s = 11390641 is a prime.
		

Crossrefs

Programs

  • Magma
    [n: n in [0..500] | IsPrime(s) where s is 1+n+n^6]; // Vincenzo Librandi, Jul 28 2014
    
  • Mathematica
    Select[Range[500], PrimeQ[1 + # + #^6] &] (* Vincenzo Librandi, Jul 28 2014 *)
  • PARI
    for(n=1,10^3,if(isprime(n^6+n+1),print1(n,", "))) \\ Derek Orr, Feb 07 2015
Showing 1-10 of 38 results. Next