G.f. x^2*(1+x)/(1-12*x+15*x^2-2*x^3).

Terms

a(0) =0a(1) =1a(2) =13a(3) =141a(4) =1499a(5) =15899a(6) =168585a(7) =1787533a(8) =18953419a(9) =200965203a(10) =2130856217a(11) =22593703397a(12) =239563527915