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.

A023269 Primes that remain prime through 2 iterations of function f(x) = 10x + 3.

Original entry on oeis.org

2, 7, 17, 19, 23, 37, 61, 67, 73, 101, 103, 173, 193, 233, 359, 383, 409, 479, 541, 557, 607, 613, 719, 809, 857, 997, 1013, 1033, 1109, 1117, 1237, 1297, 1361, 1459, 1531, 1549, 1699, 1823, 1871, 1979, 1999, 2069, 2131, 2161, 2347, 2377, 2399, 2447, 2663
Offset: 1

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Comments

Primes p such that 10*p+3 and 100*p+33 are also primes. - Vincenzo Librandi, Aug 04 2010

Crossrefs

Subsequence of A023238 and of A102338.

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and IsPrime(10*n+3) and IsPrime(100*n+33)] // Vincenzo Librandi, Aug 04 2010
  • Mathematica
    Select[Prime@ Range@ 400, Times @@ Boole@ PrimeQ@ Rest@ NestList[10 # + 3 &, #, 2] > 0 &] (* Michael De Vlieger, Sep 16 2016 *)
    Select[Prime[Range[500]],AllTrue[Rest[NestList[10#+3&,#,2]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Sep 03 2018 *)