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 21-25 of 25 results.

A139508 Primes of the form x^2 + 28x*y + y^2 for x and y nonnegative.

Original entry on oeis.org

61, 181, 601, 829, 1069, 1249, 1381, 1429, 1609, 1621, 1741, 2029, 2089, 2161, 2341, 2389, 2521, 3121, 3169, 3181, 3301, 3709, 3769, 4021, 4261, 4549, 4729, 4801, 4861, 4969, 5209, 5281, 5521, 5581, 5641, 5749, 5821, 6301, 6361, 6421, 6529, 6709, 6829
Offset: 1

Views

Author

Artur Jasinski, Apr 24 2008

Keywords

Comments

In base 12, the sequence is 51, 131, 421, 591, 751, 881, 971, 9E1, E21, E31, 1011, 1211, 1261, 1301, 1431, 1471, 1561, 1981, 1X01, 1X11, 1XE1, 2191, 2221, 23E1, 2571, 2771, 28X1, 2941, 2991, 2X61, 3021, 3081, 3241, 3291, 3321, 33E1, 3451, 3791, 3821, 3871, 3941, 3X71, 3E51, where X is 10 and E is 11. Moreover, the discriminant is 550. - Walter Kehowski, Jun 01 2008

Crossrefs

Programs

  • Mathematica
    a = {}; w = 28; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)

A139509 Primes of the form x^2 + 29x*y + y^2 for x and y nonnegative.

Original entry on oeis.org

31, 97, 211, 373, 547, 607, 661, 769, 877, 1051, 1087, 1123, 1249, 1279, 1303, 1423, 1597, 1657, 1663, 1693, 1741, 1777, 1861, 1867, 2143, 2179, 2251, 2341, 2467, 2539, 2791, 2857, 3229, 3259, 3319, 3331, 3373, 3511, 3541, 3643, 3697, 3769, 3823, 3877
Offset: 1

Views

Author

Artur Jasinski, Apr 24 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; w = 29; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)

A139510 Primes of the form x^2 + 30x*y + y^2 for x and y nonnegative.

Original entry on oeis.org

137, 193, 401, 617, 641, 953, 1009, 1129, 1289, 1297, 1801, 1913, 2129, 2137, 2377, 2473, 2657, 2713, 2801, 3049, 3257, 3313, 3329, 3593, 3889, 4001, 4057, 4153, 4201, 4337, 4649, 4657, 4729, 4817, 4937, 4993, 5009, 5153, 5209, 5441, 5657, 5849, 5881
Offset: 1

Views

Author

Artur Jasinski, Apr 24 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; w = 30; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)

A139511 Primes of the form x^2 + 31x*y + y^2 for x and y nonnegative.

Original entry on oeis.org

67, 103, 181, 199, 223, 313, 397, 463, 487, 499, 631, 643, 661, 691, 709, 883, 991, 1021, 1039, 1093, 1153, 1213, 1321, 1483, 1543, 1567, 1741, 1747, 1753, 1831, 1879, 2017, 2029, 2083, 2113, 2137, 2179, 2203, 2269, 2311, 2377, 2539, 2557, 2677, 2731
Offset: 1

Views

Author

Artur Jasinski, Apr 24 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a = {}; w = 31; k = 1; Do[Do[If[PrimeQ[n^2 + w*n*m + k*m^2], AppendTo[a, n^2 + w*n*m + k*m^2]], {n, m, 400}], {m, 1, 400}]; Union[a] (*Artur Jasinski*)

A139829 Primes of the form 4x^2+4xy+11y^2.

Original entry on oeis.org

11, 19, 59, 131, 139, 179, 211, 251, 331, 379, 419, 491, 499, 571, 619, 659, 691, 739, 811, 859, 971, 1019, 1051, 1091, 1171, 1259, 1291, 1451, 1459, 1499, 1531, 1571, 1579, 1619, 1699, 1811, 1931, 1979, 2011, 2099, 2131, 2179, 2251, 2339, 2371
Offset: 1

Views

Author

T. D. Noe, May 02 2008

Keywords

Comments

Discriminant=-160. See A139827 for more information.
Also, primes of form u^2+10v^2 with odd v, while A107145 has even v. One can transform its form as (2x+y)^2+10y^2 (where y can only be odd) and the latter is x^2+10(2y)^2. This sequence has primes {11,19} mod 20 while the second has {1,9} mod 20 and together they are the primes x^2+10y^2 (A033201) which are {1,9,11,20} mod 20. [From Tito Piezas III, Jan 01 2009]

Programs

  • Magma
    [ p: p in PrimesUpTo(3000) | p mod 40 in {11, 19}]; // Vincenzo Librandi, Jul 29 2012
  • Mathematica
    QuadPrimes2[4, -4, 11, 10000] (* see A106856 *)

Formula

The primes are congruent to {11, 19} (mod 40).
Previous Showing 21-25 of 25 results.