51666domain: NAppears in sequencesa(n) = n for n <= 2; for n > 2, a(n) = 2a(n-1) - a(n - floor(1/2 + sqrt(2(n-1)))).at n=20A096824Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 499", based on the 5-celled von Neumann neighborhood.at n=40A272562