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

Terms

a(0) =1a(1) =6a(2) =18a(3) =48a(4) =120a(5) =288a(6) =672a(7) =1536a(8) =3456a(9) =7680a(10) =16896a(11) =36864a(12) =79872a(13) =172032a(14) =368640a(15) =786432a(16) =1671168a(17) =3538944a(18) =7471104a(19) =15728640a(20) =33030144a(21) =69206016a(22) =144703488a(23) =301989888a(24) =629145600a(25) =1308622848a(26) =2717908992a(27) =5637144576a(28) =11676942336a(29) =24159191040