201320domain: NAppears in sequencesDecimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,0,1,3.at n=5A037722Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 805", based on the 5-celled von Neumann neighborhood.at n=8A273603