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.

A376013 Prime numbers of the form 3p+8 where p, p+2 and p+6 are prime numbers.

Original entry on oeis.org

23, 41, 59, 131, 311, 941, 1049, 1931, 2579, 3911, 4289, 4451, 6719, 8069, 10391, 10589, 12011, 14369, 26591, 31379, 33521, 35339, 41081, 43889, 58271, 59981, 63059, 64679, 66821, 74759, 77999, 78791, 80051, 80141, 83219, 87071, 94541, 96179
Offset: 1

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Author

Zak Seidov, Sep 06 2024

Keywords

Comments

An integer n is in this list if it is a prime number and (n-8)/3, (n-2)/3, (n+10)/3 are all prime numbers. 23 is a term because it is prime and 5, 7 and 11 are prime numbers.

Examples

			5 + 7 + 11 = 23;
11 + 13 + 17 = 41;
17 + 19 + 23 = 59;
41 + 43 + 47 = 131;
101 + 103 + 107 = 311;
311 + 313 + 317 = 941;
347 + 349 + 353 = 1049;
...
		

Crossrefs

Programs

  • Mathematica
    Select[Total /@ Select[Partition[Prime[Range[3500]], 3, 1], Differences[#] == {2, 4} &], PrimeQ] (* Amiram Eldar, Sep 06 2024 *)
  • PARI
    list(lim)=my(v=List(),p=5,q=7,s); forprime(r=11,(lim+10)\3, if(r-p==6 && q-p==2 && isprime(s=3*p+8), listput(v,s)); p=q; q=r); Vec(v) \\ Charles R Greathouse IV, Sep 18 2024

Formula

a(n) = 3*A162001(n) + 8. - Daniel Mondot, Sep 06 2024
a(n) == 5 (mod 6). - Hugo Pfoertner, Sep 06 2024
a(n) >> n log^4 n. - Charles R Greathouse IV, Sep 18 2024