295244domain: NAppears in sequencesa(n) = n*9^n - 1.at n=4A064755Sequence of sums of alternating powers of 3.at n=21A079362Numbers of the form i*9^j-1 (i=1..8, j >= 0).at n=44A140576Expansion of (1+2x-x^3+x^4)/(1-4x^2+3x^4).at n=22A181655a(n) = 5*3^n-1.at n=10A198643a(n) = 5*9^n-1.at n=5A198962