536870918domain: NAppears in sequencesa(n) = 2^(n-1)*(6*n-10)+6.at n=23A048499Least integer m whose largest prime factor > m^(n/(n+1)).at n=27A063765Semiprime nearest to 2^n. (In case of a tie, choose the smaller).at n=29A117405a(n) = 2^n + 6.at n=29A153972a(n) is the smallest number k such that 2k - sigma(k) = 2^n.at n=27A292557