Triangle: let f(t) = 1 + t + t^2 and g(t) = t + t^2, expansion of p(t) = f(t)*exp(x*g(t)).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =1a(6) =0a(7) =12a(8) =9a(9) =1a(10) =0a(11) =24a(12) =48a(13) =16a(14) =1a(15) =0a(16) =0a(17) =180a(18) =140a(19) =25a(20) =1a(21) =0a(22) =0a(23) =360a(24) =840a(25) =330a(26) =36a(27) =1a(28) =0a(29) =0