138060domain: NAppears in sequencesa(n) is the least positive even number k such that among the first k prime numbers there are exactly k/2 prime numbers where the n-th least significant bit is one, or a(n) = -1 if no such k exists.at n=12A308575Numbers k such that A372692(k) = A372692(k+1) > 1.at n=25A372693