98715domain: NAppears in sequencesa(n) = floor(e^((n-1)/2)).at n=24A005182a(n) = floor(e^(n + 1/2)).at n=11A219092Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 721", based on the 5-celled von Neumann neighborhood.at n=41A273447