79999999993domain: NAppears in sequencesa(n) = 8*10^n - 7.at n=10A100412Numbers n such that d(n)*reversal(n)=sigma(n), where d(n) is number of positive divisors of n.at n=13A104907Primes of the form 8*10^n-7.at n=4A105322Numbers n such that 2*reversal(n)=sigma(n).at n=18A105324Numbers k such that 2*reverse(k) - k = 1.at n=10A169830