a(n) = (n^3 - n)*4^n.

Terms

a(0) =0a(1) =96a(2) =1536a(3) =15360a(4) =122880a(5) =860160a(6) =5505024a(7) =33030144a(8) =188743680a(9) =1038090240a(10) =5536481280a(11) =28789702656a(12) =146565758976a(13) =732828794880