-4259domain: ZAppears in sequencesa(n) = (n^5 - 133*n^4 + 6729*n^3 - 158379*n^2 + 1720294*n - 6823316)/4.at n=20A121887First differences of number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 213", based on the 5-celled von Neumann neighborhood.at n=35A270904