47014domain: NAppears in sequencesa(n) = n*(2^n - n + 1) + 2^(n-1)*(n^2 - 3*n + 2).at n=9A191821a(n) = number of steps to reach 0 when starting from k = 3^n and repeatedly applying the map that replaces k with k - (sum of digits in base-3 representation of k).at n=12A261232Numbers k such that (12^k - 1)^2 - 2 is prime.at n=7A364076