Triangle whose (i,j)-th entry is binomial(i,j)*3^(i-j)*3^j.

Terms

a(0) =1a(1) =3a(2) =3a(3) =9a(4) =18a(5) =9a(6) =27a(7) =81a(8) =81a(9) =27a(10) =81a(11) =324a(12) =486a(13) =324a(14) =81a(15) =243a(16) =1215a(17) =2430a(18) =2430a(19) =1215a(20) =243a(21) =729a(22) =4374a(23) =10935a(24) =14580a(25) =10935a(26) =4374a(27) =729a(28) =2187a(29) =15309