2083840domain: NAppears in sequencesa(n) = ((1 + sqrt(7))^n - (1 - sqrt(7))^n)/sqrt(7).at n=12A274520Decimal representation of the diagonal from the origin to the corner of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 307", based on the 5-celled von Neumann neighborhood.at n=20A287599