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.

A336368 Primes p(n) such that gcd(n, prime(n)+prime(n+1)) = 1.

Original entry on oeis.org

2, 11, 17, 23, 31, 41, 59, 67, 73, 83, 97, 109, 127, 157, 167, 179, 191, 211, 227, 233, 241, 277, 283, 331, 353, 367, 389, 401, 431, 439, 461, 467, 499, 509, 523, 547, 563, 587, 599, 607, 617, 631, 653, 661, 677, 691, 709, 727, 739, 751, 773, 797, 829, 859
Offset: 1

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Author

Clark Kimberling, Oct 04 2020

Keywords

Comments

This sequence and A336369 partition the set of primes.

Examples

			In the following table, p(n) = A000040(n) = prime(n).
  n    p(n)   p(n)+p(n+1)   gcd
  1     2         5          1
  2     3         8          4
  3     5        12          3
  4     7        18          2
  5    11        24          1
  6    13        30          6
1 and 5 are in A336366; 2 and 3 are in A336367; 2 and 11 are in A336368; 3 and 5 are in A336369.
		

Crossrefs

Programs

  • Mathematica
    p[n_] := Prime[n];
    u = Select[Range[200], GCD[#, p[#] + p[# + 1]] == 1 &]  (* A336366 *)
    v = Select[Range[200], GCD[#, p[#] + p[# + 1]] > 1 &]   (* A336367 *)
    Prime[u] (* A336368 *)
    Prime[v] (* A336369 *)