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 11-16 of 16 results.

A135984 a(n) = 24(prime(n))+7.

Original entry on oeis.org

55, 79, 127, 175, 271, 319, 415, 463, 559, 703, 751, 895, 991, 1039, 1135, 1279, 1423, 1471, 1615, 1711, 1759, 1903, 1999, 2143, 2335, 2431, 2479, 2575, 2623, 2719, 3055, 3151, 3295, 3343, 3583, 3631, 3775, 3919, 4015, 4159, 4303, 4351, 4591, 4639, 4735
Offset: 1

Views

Author

Artur Jasinski, Dec 09 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Table[24*Prime[n] + 7, {n, 1, 100}]

A135985 Prime numbers of the form 24*p + 7 where p is prime.

Original entry on oeis.org

79, 127, 271, 463, 751, 991, 1039, 1279, 1423, 1471, 1759, 1999, 2143, 2719, 3343, 3583, 3631, 3919, 4159, 4591, 4639, 4783, 5503, 5743, 5791, 7039, 7951, 8623, 9103, 9199, 9343, 9631, 10111, 10399, 10639, 11071, 11119, 11503, 12511
Offset: 1

Views

Author

Artur Jasinski, Dec 09 2007

Keywords

Crossrefs

Programs

  • Maple
    select(t -> isprime(t) and isprime((t-7)/24), [seq(p,p=7..20000,24)]); # Robert Israel, Oct 16 2018
  • Mathematica
    a = {}; Do[If[PrimeQ[24(Prime[n]) + 7], AppendTo[a, 24(Prime[n]) + 7]], {n, 1, 100}]; a

A139527 Numbers n such that numbers 24n+5 are primes.

Original entry on oeis.org

0, 1, 2, 4, 6, 7, 8, 11, 12, 13, 16, 19, 21, 23, 27, 28, 29, 32, 33, 34, 39, 42, 44, 46, 49, 51, 53, 54, 57, 62, 67, 68, 71, 72, 78, 79, 81, 82, 83, 86, 89, 92, 93, 96, 97, 98, 99, 103, 106, 109, 112, 114, 116, 118, 119, 121, 123, 134, 141, 142, 144, 147, 148, 149, 153, 154
Offset: 1

Views

Author

Artur Jasinski, Apr 25 2008

Keywords

Comments

Numbers n such that:
24n+1 is prime see A111174, primes 24n+1 see A107008
24n+5 is prime see A139527, primes 24n+5 see A107003
24n+7 is prime see A139483, primes 24n+7 see A107006
24n+11 is prime A139528, primes 24n+11 see A107007
24n+13 is prime see A139529, primes 24n+13 see A139530
24n+17 is prime see A139531, primes 24n+17 see A107181
24n+19 is prime see A139532, primes 24n+19 see A141373
24n+23 is prime see A131210, primes 24n+23 see A134517

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[24 n + 5], AppendTo[a, n]], {n, 0, 200}]; a
    Select[Table[(Prime[n]-5)/24,{n,800}],IntegerQ] (* Harvey P. Dale, Feb 25 2016 *)

A290402 Primes congruent to {7, 17} mod 24.

Original entry on oeis.org

7, 17, 31, 41, 79, 89, 103, 113, 127, 137, 151, 199, 223, 233, 257, 271, 281, 353, 367, 401, 439, 449, 463, 487, 521, 569, 593, 607, 617, 631, 641, 727, 751, 761, 809, 823, 857, 881, 919, 929, 953, 967, 977, 991, 1039, 1049, 1063, 1087, 1097, 1193, 1217, 1231
Offset: 1

Views

Author

Arkadiusz Wesolowski, Aug 03 2017

Keywords

Comments

All these primes do not divide any number of the form 3*2^k - 1. Therefore, they are not in A001915.

Crossrefs

Programs

  • Magma
    [p: p in PrimesUpTo(1231) | p mod 24 in {7, 17}];
  • Mathematica
    Select[Prime@Range[202], MemberQ[{7, 17}, Mod[#, 24]] &]

Formula

A135658 Nonprimes of the form 4x^2-4xy+7y^2.

Original entry on oeis.org

4, 15, 16, 24, 28, 36, 40, 55, 60, 63, 64, 87, 88, 96, 100, 112, 124, 132, 135, 144, 159, 160, 168, 175, 196, 216, 220, 231, 232, 240, 247
Offset: 1

Views

Author

Artur Jasinski, Nov 25 2007

Keywords

Comments

Because 4x^2-4*x*y+7*y^2 = (2*x-y)^2+6*y^2, this is a subsequence of A002481. - R. J. Mathar, Jan 18 2021

Crossrefs

Programs

  • Mathematica
    Do[Do[w = 4x^2 - 4x y + 7y^2; If[w > 0, If[PrimeQ[w],[null], AppendTo[a, w]]], {x, 0, 100}], {y, 0, 100}]; Union[a]

A256172 Primes of the form 6*p + 1 with p prime that are also of the form x^2 + 27*y^2 and congruent to 7 mod 24.

Original entry on oeis.org

31, 223, 439, 1399, 2383, 2767, 3343, 3463, 3607, 4567, 6079, 7927, 8167, 8287, 8719, 10159, 10663, 11959, 14503, 15559, 15727, 17383, 18223, 19087, 20743, 21487, 21559, 24007, 25639, 26647, 27103, 27583, 28807, 28879, 29167, 29599, 31183, 32359, 33343
Offset: 1

Views

Author

Arkadiusz Wesolowski, Jun 01 2015

Keywords

Comments

a(n) divides 2^m - 1, where m = (a(n) - 7)/6 + 1.

Crossrefs

Subsequence of A122094.

Formula

A014752 INTERSECT A051644 INTERSECT A107006.
Previous Showing 11-16 of 16 results.