a(n) = n*(n+3)*2^(n-3).

Terms

a(0) =1a(1) =5a(2) =18a(3) =56a(4) =160a(5) =432a(6) =1120a(7) =2816a(8) =6912a(9) =16640a(10) =39424a(11) =92160a(12) =212992a(13) =487424a(14) =1105920a(15) =2490368a(16) =5570560a(17) =12386304a(18) =27394048a(19) =60293120a(20) =132120576a(21) =288358400a(22) =627048448a(23) =1358954496a(24) =2936012800a(25) =6325010432a(26) =13589544960a(27) =29125246976