a(n) = n*4^n.

Terms

a(0) =0a(1) =4a(2) =32a(3) =192a(4) =1024a(5) =5120a(6) =24576a(7) =114688a(8) =524288a(9) =2359296a(10) =10485760a(11) =46137344a(12) =201326592a(13) =872415232a(14) =3758096384a(15) =16106127360a(16) =68719476736a(17) =292057776128