%I
%S 3,5,11,13,17,23,29,31,37,43,47,59,67,71,97,101,103,107,109,113,137,
%T 149,157,181,197,229,233,239,251,263,269,271,281,283,307,311,313,331,
%U 347,349,353,359,367,383,431,467,503,523,563,571,587,607,643,647,683,691
%N Primes p such that there exist positive integer k and prime q with p > q and 3^k = p + 2q or 3^k = q + 2p.
%C a(n) is the greater of primes (p,q) in representations of a power of 3 in LemoineLevy's form p+2q (see A046927)
%C If 3^n=p+2q, then 3^(n1)<=max(p,q)<3^n. Therefore the sets of greater primes for different powers of 3 do not intersect.
%F If A(x) is the counting function of a(n)<=x, then A(x)=O(xloglogx/(logx)^2).
%e 27=5+2*11=13+2*7=17+2*5=23+2*2, so that 11,13,17 and 23 are in the sequence.
%o (PARI) aa(n)={my(v=[]); forprime(p=2,n\2,q=np*2; if(isprime(q),v=concat(v,(max(p,q))))); vecsort(v,,8)};
%o for(n=2, 7, v=aa(3^n); for(i=1,#v,print1(v[i], ", ")))
%Y Cf. A103151, A086081, A152451
%K nonn
%O 1,1
%A _Vladimir Shevelev_, Dec 05 2008, Dec 12 2008
%E Program and editing by _Charles R Greathouse IV_, Nov 02 2009
