a(n) = n*(2^n + 1).

Terms

a(0) =0a(1) =3a(2) =10a(3) =27a(4) =68a(5) =165a(6) =390a(7) =903a(8) =2056a(9) =4617a(10) =10250a(11) =22539a(12) =49164a(13) =106509a(14) =229390a(15) =491535a(16) =1048592a(17) =2228241a(18) =4718610a(19) =9961491a(20) =20971540a(21) =44040213a(22) =92274710a(23) =192938007a(24) =402653208a(25) =838860825a(26) =1744830490a(27) =3623878683a(28) =7516192796