210210210domain: NAppears in sequencesDecimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 2,1,0.at n=8A037527Ternary numbers with equal numbers of 0's, 1's and 2's and such that read left-to-right at all times the number of 2's >= number of 1's >= number of 0's.at n=6A134236