43186domain: NAppears in sequencesNumbers k such that sigma(k) = sigma(k+11).at n=19A015881Numbers k such that 10^k + 9 is prime.at n=18A088275a(n) is the period of the oscillating pattern formed by a diagonal line of 2*n cells in the Life-like cellular automaton B2e3ijkn4cz5/S236.at n=50A323382