22222222221domain: NAppears in sequencesExpansion of g.f. x*(1+10*x)/((1-x)*(1-10*x^2)).at n=21A094623Ternary equivalents of A109682.at n=10A109684Second elements of the pairs listed in A134514.at n=19A134585a(n) = (2*10^n - 11)/9.at n=10A165402Expansion of x*(1 + 2*x + 10*x^2)/((1 - x^2)*(1 - 10*x^2)).at n=21A322925