-8019domain: ZAppears in sequencesExpansion of 1/(3*x^2 - 3*x + 1)^2.at n=12A115052Expansion of (1-27x^2-108x^3)/((1-3x)^2*(1+3x+9x^2)).at n=6A168072Dirichlet inverse of A001160, sigma_5.at n=17A178448