OFFSET
1,8
COMMENTS
Empirically, such primes always exist for n >= 10, i.e., 2n-1 >= 19, whence a(n) >= 3 for all n >= 10. Again empirically, a(n) ~ 2n/3 as n -> oo and a(n) is always close to 2n/3.
This is the bisection (every other term) of A278922, whose terms with even indices are all equal to 2 (or 0).
LINKS
PROG
(PARI) a(n, p=(n=2*n-1)\3-1)=while(p=precprime(p-1), forprime(q=p+1, (n-p-1)\2, isprime(n-p-q)&&return(p)))
CROSSREFS
KEYWORD
nonn
AUTHOR
M. F. Hasler, Dec 01 2016
STATUS
approved