628292358729domain: NAppears in sequencesa(n) = (8^n - 1)/7.at n=14A023001Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 2, 1, 0.at n=19A037521a(n) = Sum_{j=0..13} n^j.at n=8A104376a(n) = a(n-1) + 2*a(n-2) if n even, or 3*a(n-1) + 4*a(n-2) if n odd, starting with 0, 1.at n=28A299913