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.

A338324 Primes p such that there exist k and m with p < k < q < m < r such that p + k, q + k, q + m and r + m are all primes, where q and r are the next two primes after p.

Original entry on oeis.org

23, 29, 47, 199, 523, 709, 797, 809, 991, 1063, 1163, 1753, 1789, 1801, 2161, 2393, 2477, 2549, 2693, 2917, 3469, 3491, 4363, 4423, 4691, 5039, 5051, 5081, 5743, 6269, 6607, 7069, 7351, 7607, 7883, 8513, 9103, 9137, 9391, 9601, 9859, 10193, 10343, 10357, 11003, 11119, 11321, 11789, 11941, 13049
Offset: 1

Views

Author

J. M. Bergot and Robert Israel, Oct 22 2020

Keywords

Comments

Members p of A336300 such that the next prime after p is also in A336300.

Examples

			a(3) = 47 is in the sequence because 47 is prime, the next two primes are 53 and 59, and with k - 50 and m = 54, all of 47+50=97, 53+50=103, 53+54=107 and 59+54=113 are prime.
		

Crossrefs

Cf. A336300.

Programs

  • Maple
    R:= NULL: count:= 0: thisp:= false:
    q:= 2: r:= 3:
    while count < 100 do
      lastp:= thisp; thisp:= false;
      p:= q; q:= r; r:= nextprime(r);
      for k from (q+1)/2 to (r-1)/2 do
        if isprime(q+2*k) and isprime(r+2*k) then
           thisp:= true; break
        fi
      od;
      if thisp and lastp then R:= R, p; count:= count+1 fi;
    od:
    R;