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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A033211 Primes of form x^2 + 14*y^2.

Original entry on oeis.org

23, 127, 137, 151, 233, 239, 281, 359, 431, 449, 487, 673, 743, 751, 911, 953, 967, 977, 1033, 1087, 1103, 1129, 1303, 1409, 1423, 1439, 1481, 1663, 1759, 1871, 1873, 2017, 2039, 2081, 2129, 2137, 2207
Offset: 1

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Author

Keywords

References

  • Cohn, Harvey. A classical invitation to algebraic numbers and class fields. With two appendices by Olga Taussky: "Artin's 1932 Göttingen lectures on class field theory" and "Connections between algebraic number theory and integral matrices". Universitext. Springer-Verlag, New York-Heidelberg, 1978. xiii+328 pp. ISBN: 0-387-90345-3; MR0506156 (80c:12001). See p. 158.
  • David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989. See pp. ix, 115, etc.

Crossrefs

Subsequence of A033207. Primes in A244037.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 14, 10000] (* see A106856 *)

A033235 Primes of the form x^2 + 55*y^2.

Original entry on oeis.org

59, 71, 199, 229, 251, 269, 311, 379, 389, 499, 509, 631, 661, 691, 751, 839, 881, 929, 1049, 1061, 1171, 1181, 1279, 1321, 1409, 1439, 1499, 1571, 1609, 1699, 1721, 1741, 1901, 1951, 2029, 2069, 2269
Offset: 1

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Keywords

Comments

Also primes of the form x^2 - xy + 14y^2 with x and y nonnegative. - T. D. Noe, May 08 2005
From Lechoslaw Ratajczak, Apr 09 2017: (Start)
Conjecture: consecutive elements of this sequence are consecutive primes satisfying the congruence b(k) == 1 (mod k) for k>0, where b(k) is recursive sequence defined as follows: b(k) = -b(k-1) - b(k-2) + b(k-3) - b(k-4) with b(0)=2, b(1)=1, b(2)=0, b(3)=-1.
(b(59) - 1) mod 59 = (-496870918 - 1) mod 59 = 0, 59 = a(1).
(b(71) - 1) mod 71 = (88081764473 - 1) mod 71 = 0, 71 = a(2).
For 10^6 consecutive positive integers there are 9748 prime solutions and 5 nonprime (1, 586, 2935, 17161, 429737) solutions of the congruence. (End)

References

  • David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 55, 10000] (* see A106856 *)

A033246 Primes of form x^2+71*y^2.

Original entry on oeis.org

71, 107, 293, 509, 643, 647, 739, 971, 1013, 1039, 1123, 1217, 1361, 1367, 1373, 1423, 1663, 1811, 2083, 2099, 2239, 2309, 2351, 2557, 2657, 2677, 2917, 3181, 3343, 3517, 3533, 3539, 3623, 3671, 3803
Offset: 1

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Author

Keywords

Comments

Also primes of the form x^2-xy+18y^2 with x and y nonnegative. - T. D. Noe, May 08 2005

References

  • David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 71, 10000] (* see A106856 *)

A033251 Primes of form x^2+79*y^2.

Original entry on oeis.org

79, 83, 179, 223, 317, 397, 479, 541, 563, 677, 727, 757, 811, 863, 907, 941, 967, 1103, 1277, 1289, 1433, 1489, 1523, 1553, 1867, 1889, 1979, 1993, 1997, 2011, 2039, 2311, 2341, 2383, 2459, 2551, 2579
Offset: 1

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Author

Keywords

Comments

Also primes of the form x^2-xy+20y^2 with x and y nonnegative. - T. D. Noe, May 08 2005

References

  • David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 79, 10000] (* see A106856 *)

A033256 Primes of form x^2+87*y^2.

Original entry on oeis.org

103, 151, 283, 349, 373, 397, 487, 571, 709, 787, 877, 883, 1039, 1459, 1531, 1567, 1753, 2017, 2029, 2179, 2203, 2239, 2371, 2383, 2557, 2617, 2659, 2719, 2749, 2791, 2851, 3181, 3253, 3301, 3331, 3373
Offset: 1

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Keywords

Comments

Also primes of the form x^2-xy+22y^2 with x and y nonnegative. - T. D. Noe, May 08 2005

References

  • David A. Cox, "Primes of the Form x^2 + n y^2", Wiley, 1989.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 87, 10000] (* see A106856 *)

A105389 Primes of the form x^2 + 32 y^2, also primes p with h(-p) divisible by 8.

Original entry on oeis.org

41, 113, 137, 257, 313, 337, 353, 409, 457, 521, 569, 577, 593, 761, 809, 857, 881, 953, 1129, 1153, 1201, 1217, 1249, 1321, 1553, 1601, 1657, 1777, 1889, 1993
Offset: 1

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Author

John L. Drost, May 01 2005

Keywords

Examples

			41 = 9 + 32 * 1, 113 = 81 + 32 *1, 137 = 9 + 32*4
		

References

  • Barrucand, P. and Cohn, H. Note on primes of the form x^2 + 32 y^2, class number and residuacity, Journal fur die reine und angewandte Mathematik, v.238, pp. 67-70.

Programs

  • Mathematica
    QuadPrimes2[1, 0, 32, 10000] (* see A106856 *)
    (* Second program: *)
    max = 10^4; Table[yy = {y, 1, Floor[Sqrt[(max - x^2)/32]]}; Table[x^2 + 32 y^2, yy // Evaluate], {x, 1, Floor[Sqrt[max]]}] // Flatten // Union // Select[#, # <= max && PrimeQ[#]&]& (* Jean-François Alcover, Oct 04 2018 *)

A106866 Primes of the form 2x^2+xy+3y^2, with x and y nonnegative.

Original entry on oeis.org

2, 3, 13, 41, 71, 127, 139, 179, 257, 269, 311, 331, 409, 439, 443, 461, 541, 587, 673, 739, 761, 823, 887, 967, 1051, 1061, 1087, 1129, 1153, 1223, 1237, 1277, 1373, 1381, 1409, 1427, 1439, 1567, 1619, 1733, 1741, 1783, 1933, 1973, 2017, 2063
Offset: 1

Views

Author

T. D. Noe, May 09 2005

Keywords

Comments

Discriminant=-23.
For even x we generate A309139. - R. J. Mathar, Aug 22 2019

Programs

  • Mathematica
    QuadPrimes2[2, 1, 3, 10000] (* see A106856 *)

A106890 Primes of the form x^2 + xy + 11y^2, with x and y nonnegative.

Original entry on oeis.org

11, 13, 17, 23, 31, 41, 47, 53, 59, 67, 79, 83, 101, 103, 107, 109, 127, 139, 167, 181, 193, 197, 229, 239, 251, 281, 283, 293, 307, 311, 317, 337, 353, 359, 367, 379, 397, 401, 431, 439, 443, 461, 479, 487, 509, 541, 547, 557, 563, 569, 599, 613, 617, 619
Offset: 1

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Author

T. D. Noe, May 09 2005

Keywords

Comments

Discriminant = -43.
Rational primes that decompose in the field Q(sqrt(-43)). - N. J. A. Sloane, Dec 25 2017

Programs

  • Mathematica
    QuadPrimes2[1, 1, 11, 10000] (* see A106856 *)

A106915 Primes of the form 3x^2 + 2xy + 5y^2, with x and y any integer.

Original entry on oeis.org

3, 5, 13, 19, 59, 61, 83, 101, 131, 139, 157, 173, 181, 227, 229, 251, 269, 283, 293, 307, 349, 397, 419, 461, 467, 509, 523, 563, 587, 619, 643, 661, 677, 691, 733, 773, 787, 797, 811, 829, 853, 859, 941, 971, 997, 1013, 1021, 1069, 1091, 1109, 1123
Offset: 1

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Author

T. D. Noe, May 09 2005

Keywords

Comments

Discriminant = -56.
Also primes congruent to {3,5,13,19,27,45} mod 56. - Vincenzo Librandi, Jul 02 2016
The theta series for the quadratic form 3x^2 + 2xy + 5y^2 is the g.f. of A028928. - Michael Somos, Jul 02 2016
Legendre symbol (-14, a(n)) = Kronecker symbol (a(n), 14) = 1. Also, this sequence lists primes p such that Kronecker symbol (p, 2) = Legendre symbol (p, 7) = -1, i.e., primes p == 3, 5 (mod 8) and 3, 5, 6 (mod 7). - Jianing Song, Sep 04 2018

Examples

			59 is in the sequence since it is prime, and 59 = 3x^2 + 2xy + 5y^2 with x = 3 and y = 2. - _Michael B. Porter_, Jul 02 2016
		

Crossrefs

Cf. A028928.

Programs

  • Magma
    [p: p in PrimesUpTo(3000) | p mod 56 in {3,5,13,19,27,45}]; // Vincenzo Librandi, Jul 02 2016
  • Mathematica
    Union[QuadPrimes2[3, 2, 5, 10000], QuadPrimes2[3, -2, 5, 10000]] (* see A106856 *)
    Select[Prime@Range[600], MemberQ[{3, 5, 13, 19, 27, 45}, Mod[#, 56]] &] (* Vincenzo Librandi, Jul 02 2016 *)

A106919 Primes of the form 3x^2+xy+5y^2, with x and y any integer.

Original entry on oeis.org

3, 5, 7, 19, 29, 41, 53, 79, 107, 127, 137, 167, 181, 193, 199, 239, 241, 251, 257, 263, 271, 277, 281, 293, 307, 311, 331, 359, 379, 433, 449, 487, 491, 499, 523, 557, 577, 593, 599, 607, 617, 619, 643, 647, 653, 661, 709, 757, 761, 829, 853, 877, 883, 907
Offset: 1

Views

Author

T. D. Noe, May 09 2005

Keywords

Comments

Discriminant=-59.
Primes p such that the polynomial x^3-2x^2-1 is irreducible over Zp. The polynomial discriminant is also -59. - T. D. Noe, May 13 2005

Programs

  • Mathematica
    Union[QuadPrimes2[3, 1, 5, 10000], QuadPrimes2[3, -1, 5, 10000]] (* see A106856 *)
Previous Showing 51-60 of 574 results. Next