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.

A023238 Primes p such that 10*p + 3 is also prime.

Original entry on oeis.org

2, 5, 7, 11, 17, 19, 23, 29, 31, 37, 43, 59, 61, 67, 73, 101, 103, 109, 137, 149, 173, 191, 193, 197, 199, 211, 227, 229, 233, 239, 263, 269, 271, 283, 331, 337, 353, 359, 367, 373, 379, 383, 401, 409, 449, 467, 479, 499, 523, 541, 557, 569, 607, 613, 617, 647, 673, 683
Offset: 1

Views

Author

David W. Wilson

Keywords

Links

Crossrefs

Cf. A023239.
Subsequence of A102338.

Programs

  • Magma
    [n: n in [0..1000] | IsPrime(n) and IsPrime(10*n+3)] // Vincenzo Librandi, Nov 20 2010
  • Maple
    A023238:=n->`if`(isprime(n) and isprime(10*n+3), n, NULL): seq(A023238(n), n=1..10^3); # Wesley Ivan Hurt, Sep 08 2016
  • Mathematica
    Select[Prime[Range[200]], PrimeQ[10# + 3] &] (* Alonso del Arte, Jun 24 2014 *)

A164569 Primes p such that 11*p+8 are prime numbers.

Original entry on oeis.org

3, 13, 31, 73, 79, 151, 163, 181, 193, 241, 283, 349, 373, 379, 409, 421, 463, 601, 631, 673, 751, 769, 811, 829, 853, 883, 991, 1021, 1039, 1063, 1171, 1201, 1303, 1381, 1423, 1429, 1453, 1459, 1471, 1543, 1549, 1579, 1609, 1621, 1663, 1669, 1789, 1801
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Aug 16 2009

Keywords

Comments

Apart from the first term, a(n) = 1 (mod 6).

Examples

			11*3+8=41, ..

Crossrefs

Cf. A023212, A023217, A023224, A023230, A023239

Programs

  • Mathematica
    lst={};Do[p=Prime[n];If[PrimeQ[11*p+8],AppendTo[lst,p]],{n,6!}];lst
Select[Prime[Range[500]],PrimeQ[11#+8]&] (* Harvey P. Dale, Jul 17 2011 *)

Extensions

Comment from Charles R Greathouse IV, Oct 12 2009

A164570 Primes p such that 8*p-3 and 8*p+3 are also prime numbers.

Original entry on oeis.org

2, 5, 7, 13, 47, 103, 107, 127, 163, 233, 293, 337, 383, 433, 443, 467, 503, 673, 677, 733, 797, 877, 1087, 1093, 1153, 1217, 1223, 1307, 1637, 1933, 2053, 2087, 2137, 2423, 2477, 2543, 2633, 2687, 2857, 2917, 3163, 3373, 3407, 3467, 3767, 3793, 3877
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Aug 16 2009

Keywords

Comments

Subsequence of A023229. [R. J. Mathar, Aug 26 2009]
Primes of the form A087695(k)/8. [R. J. Mathar, Aug 26 2009]

Examples

			For p=2, 8*2-3=13 and 8*2+3=19 are prime numbers, which adds p=2 to the sequence
For p=5, 8*5-3=37 and 8*5+3=43 are prime numbers, which adds p=5 to the sequence.

Links

Crossrefs

Cf. A023212, A023217, A023224, A023230, A023239, A060212, A106015, A124098, A125272, A127430, A153768, A164566, A164567, A164568, A164569.

Programs

  • Magma
    [p: p in PrimesUpTo(3000) | IsPrime(8*p-3) and IsPrime(8*p+3)]; // Vincenzo Librandi, Apr 09 2013
  • Mathematica
    lst={};Do[p=Prime[n];If[PrimeQ[8*p-3]&&PrimeQ[8*p+3],AppendTo[lst,p]], {n,7!}];lst
Select[Prime[Range[1000]], And@@PrimeQ/@{8 # + 3, 8 # - 3}&] (* Vincenzo Librandi, Apr 09 2013 *)
Select[Prime[Range[1000]],AllTrue[8#+{3,-3},PrimeQ]&] (* Harvey P. Dale, May 05 2023 *)

Extensions

Comments turned into examples by R. J. Mathar, Aug 26 2009
Showing 1-3 of 3 results.

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

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