43370domain: NAppears in sequencesNumber of primes p with 2^n < p < 3^n.at n=11A076958a(n) = Sum_{k=0..floor(n/4)} C(n-3*k,k+1).at n=32A098578Number of primes p with 2^n <= p < 3^n.at n=11A163825a(n) = a(n-2) + a(n-3) + a(n-4) for n>3, a(0)=1, a(1)=a(2)=0, a(3)=2.at n=31A277253