Triangle of coefficients of a sequence of binomial type polynomials.

Terms

a(0) =3a(1) =6a(2) =9a(3) =30a(4) =54a(5) =27a(6) =222a(7) =468a(8) =324a(9) =81a(10) =2190a(11) =5130a(12) =4320a(13) =1620a(14) =243a(15) =27006a(16) =68400a(17) =65610a(18) =30780a(19) =7290a(20) =729a(21) =399630a(22) =1076166a(23) =1135890a(24) =618030a(25) =187110a(26) =30618a(27) =2187a(28) =6899262a(29) =19532268