a(n) = (1/4!)*3^(n+2)*(n+7)*(n+2)*(n+1)*(n).

Terms

a(0) =54a(1) =729a(2) =6075a(3) =40095a(4) =229635a(5) =1194102a(6) =5786802a(7) =26572050a(8) =116917020a(9) =496897335a(10) =2051893701a(11) =8269753401a(12) =32643763425a(13) =126557359740a(14) =482984209620