a(n) = Sum_{k=0..ceiling(n/2)} k*binomial(n,k).

Terms

a(0) =0a(1) =1a(2) =2a(3) =9a(4) =16a(5) =55a(6) =96a(7) =294a(8) =512a(9) =1467a(10) =2560a(11) =7018a(12) =12288a(13) =32630a(14) =57344a(15) =148620a(16) =262144a(17) =666451a(18) =1179648a(19) =2952258a(20) =5242880a(21) =12949986a(22) =23068672a(23) =56346964a(24) =100663296a(25) =243517150a(26) =436207616a(27) =1046377764a(28) =1879048192a(29) =4474004812