Cube of lower triangular normalized binomial matrix.

Terms

a(0) =1a(1) =3a(2) =1a(3) =9a(4) =6a(5) =1a(6) =27a(7) =27a(8) =9a(9) =1a(10) =81a(11) =108a(12) =54a(13) =12a(14) =1a(15) =243a(16) =405a(17) =270a(18) =90a(19) =15a(20) =1a(21) =729a(22) =1458a(23) =1215a(24) =540a(25) =135a(26) =18a(27) =1a(28) =2187a(29) =5103