3486784381domain: NAppears in sequencesa(n) = 3^n - n.at n=20A024024Primes of the form 3^n - n.at n=3A224420Primes of the form 3^k - 20.at n=7A289723a(n) is the least prime p such that Omega(p + n) = n where Omega is A001222, or 0 if no such prime exists.at n=19A345740