a(n) = n*6^(n-1).

Terms

a(0) =1a(1) =12a(2) =108a(3) =864a(4) =6480a(5) =46656a(6) =326592a(7) =2239488a(8) =15116544a(9) =100776960a(10) =665127936a(11) =4353564672a(12) =28298170368a(13) =182849716224