Triangle reads by rows: T(n,k) = coefficient of x^k in (x^3-2*x^2-2*x+1)^n.

Terms

a(0) =1a(1) =-2a(2) =-2a(3) =1a(4) =1a(5) =-4a(6) =0a(7) =10a(8) =0a(9) =-4a(10) =1a(11) =1a(12) =-6a(13) =6a(14) =19a(15) =-24a(16) =-24a(17) =19a(18) =6a(19) =-6a(20) =1a(21) =1a(22) =-8a(23) =16a(24) =20a(25) =-80a(26) =-8a(27) =134a(28) =-8a(29) =-80