38347924domain: NAppears in sequencesExpansion of g.f. (1 - 2*x^2 - 3*x^3)/((1 - x^3)*(1 - 2*x)).at n=28A063823a(n) = a(n-3) + 2^(n-4) with a(1) = 1, a(2) = 2, a(3) = 1.at n=28A166578