A231483 Smallest k > A082467(n) such that n-k and n+k are both prime.

9, 8, 15, 18, 7, 12, 15, 10, 15, 18, 7, 28, 15, 10, 27, 12, 7, 24, 15, 8, 21, 18, 5, 30, 15, 8, 27, 24, 11, 18, 9, 10, 15, 30, 13, 18, 15, 10, 21, 30, 7, 42, 21, 10, 33, 18, 7, 30, 21, 10, 9, 18, 11, 30, 27, 8, 33, 24, 11, 48, 21, 8, 21, 30

Offset

20,1

Comments

Starting at n=20 just because there are some n<20 without solution like for n=19, for the least k (A082467) it start at 4 as no solution for n<4.

Links

Pierre CAMI, Table of n, a(n) for n = 20..10000

Prog

(PARI) a(n) = {k=1; while(isprime(n-k)*isprime(n+k) == 0, k++); k++; while(isprime(n-k)*isprime(n+k) == 0, k++); k; } \\ Michel Marcus, Nov 10 2013

Crossrefs

Cf. A082467.

Sequence in context: A272962 A137392 A307639 * A309656 A370882 A363327

Adjacent sequences: A231480 A231481 A231482 * A231484 A231485 A231486

Keyword

nonn

Author

Pierre CAMI, Nov 09 2013

Status

approved