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.

A368691 Primes p such that p + 4 * q is prime, where q is the next prime after p.

Original entry on oeis.org

3, 23, 31, 73, 83, 157, 167, 211, 251, 353, 373, 443, 467, 503, 509, 523, 541, 571, 647, 727, 751, 941, 947, 977, 1033, 1069, 1123, 1201, 1259, 1361, 1381, 1493, 1511, 1531, 1553, 1613, 1759, 1811, 2011, 2207, 2333, 2351, 2383, 2399, 2417, 2543, 2777, 2927, 3061, 3067, 3083, 3301, 3331, 3511
Offset: 1

Views

Author

Zak Seidov and Robert Israel, Jan 03 2024

Keywords

Examples

			a(3) = 31 is a term because 31 is prime, the next prime is 37, and 31 + 4 * 37 = 179 is prime.
		

Crossrefs

Cf. A175914.

Programs

  • Maple
    filter:= proc(p) local q;
      if not isprime(p) then return false fi;
      q:= nextprime(p);
      isprime(p+4*q)
    end proc:
    select(filter, [seq(i,i=3..10000,2)]);
  • Mathematica
    f[p_] := Module[{q}, If[!PrimeQ[p], Return[False]]; q = NextPrime[p]; PrimeQ[p + 4*q]];Select[Range[3,3511, 2],f] (* James C. McMahon, Jan 03 2024 *)