212993domain: NAppears in sequencesa(n) = (n-1)*2^n + 1.at n=14A000337Numbers k such that phi(k) + phi(k+1) = sigma(k).at n=20A067799Duplicate of A000337.at n=14A082753a(n) = 2*a(n-1) - 1 with a(0)=14.at n=14A168596