97059domain: NAppears in sequencesa(1) = 4; a(n) is smallest semiprime > 2*a(n-1).at n=14A117880Record values in A197944.at n=20A197946Odd numbers n for which the number of iterations to reach the largest equals number of iterations to reach 1 from the largest in Collatz (3x+1) trajectory of n.at n=30A224533