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 1-3 of 3 results.

A023224 Primes p such that 7*p + 4 is also prime.

Original entry on oeis.org

7, 19, 37, 61, 79, 97, 139, 151, 157, 211, 229, 271, 307, 349, 379, 457, 487, 547, 571, 601, 607, 619, 631, 709, 751, 757, 769, 829, 877, 907, 937, 997, 1021, 1069, 1117, 1129, 1237, 1249, 1291, 1327, 1429, 1447, 1471, 1489, 1549, 1567, 1579, 1621, 1627, 1699
Offset: 1

Views

Author

David W. Wilson

Keywords

Comments

Subsequence of A024902. All terms are congruent to 1 mod 6 because 7(6n + 5) + 4 is divisible by 3. - John Cerkan, Jul 08 2016

Links

Crossrefs

Cf. A024902.

Programs

  • Magma
    [n: n in [0..100000] | IsPrime(n) and IsPrime(7*n+4)] // Vincenzo Librandi, Nov 19 2010
  • Maple
    A023224:=n->`if`(isprime(n) and isprime(7*n+4), n, NULL): seq(A023224(n), n=1..5000); # Wesley Ivan Hurt, Jul 08 2016
  • Mathematica
    Select[Prime[Range[300]], PrimeQ[7# + 4] &] (* Alonso del Arte, Nov 21 2018 *)
  • PARI
    lista(nn) = for(p=2, nn, if(isprime(7*p+4), print1(p, ", "))); \\ Altug Alkan, Jul 08 2016

A111250 Numbers n such that 7*n + 10 is prime.

Original entry on oeis.org

1, 3, 7, 9, 13, 21, 27, 31, 33, 37, 39, 43, 49, 51, 57, 67, 73, 79, 81, 87, 91, 93, 109, 111, 117, 121, 133, 139, 141, 147, 157, 159, 163, 169, 177, 181, 183, 187, 193, 207, 211, 219, 223, 229, 231, 237, 241, 249, 259, 267, 271, 277, 297, 303, 319, 333, 339, 343
Offset: 1

Views

Author

Parthasarathy Nambi, Oct 31 2005

Keywords

Comments

One less than the entry of A089033 at the same index.

Examples

			If n=117 then 7*n + 10 = 829 (prime).

Links

Crossrefs

Cf. A105772, A024902, A024900.

Programs

  • Magma
    [ n: n in [0..1500] | IsPrime(7*n + 10) ] // Vincenzo Librandi, Jan 31 2011
  • Mathematica
    Select[Range[400],PrimeQ[7#+10]&] (* Harvey P. Dale, Mar 25 2021 *)
  • PARI
    for(n=1,453,if(isprime(7*n + 10),print1(n,",")))

Extensions

Extended by Lambert Klasen (lambert.klasen(AT)gmx.net), Nov 02 2005

A111249 Numbers n such that 7*n + 8 is prime.

Original entry on oeis.org

3, 5, 9, 15, 17, 27, 29, 33, 39, 47, 53, 59, 63, 65, 69, 77, 87, 89, 93, 95, 99, 105, 107, 117, 125, 129, 135, 137, 143, 149, 155, 165, 183, 185, 195, 203, 209, 213, 225, 227, 237, 243, 245, 267, 275, 285, 287, 297, 303, 305, 315, 323, 327, 329, 333, 339, 345
Offset: 1

Views

Author

Parthasarathy Nambi, Oct 31 2005

Keywords

Comments

One less than the associated entry in A024905.

Examples

			If n=125 then 7*n + 8 = 883 (prime).

Crossrefs

Cf. A024900, A024902, A024905, A105772.

Programs

Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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