930022domain: NAppears in sequencesa(1)=1, a(n) = n*3^(n-1) + a(n-1).at n=10A014915a(n) = smallest number m which can be obtained in n ways by subtracting twice a triangular number from a perfect square.at n=12A078714Expansion of -2*x*(-8-12*x+9*x^2) / ( (x-1)*(3*x-1)*(3*x+1)*(1+x) ).at n=11A120468a(n) = (7*9^n + 1)/4.at n=6A199565