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
KEYWORD
nonn
AUTHOR
Pierre CAMI, Nov 09 2013
STATUS
approved