254186582833domain: NAppears in sequencesa(n) = (1 - (-9)^n)/10.at n=12A014991Gaussian binomial coefficient [ n,12 ] for q=-9.at n=1A015432a(n+1) = 8*a(n) + 9*a(n-1), a(0) = 0, a(1) = 1.at n=13A015577Cyclotomic polynomials at x=-9.at n=13A020508Partial sums of round(3^n/5).at n=25A178543a(n) = Sum_{j=0..12} (-n)^j.at n=9A266229