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

Terms

a(0) =1a(1) =8a(2) =40a(3) =176a(4) =736a(5) =3008a(6) =12160a(7) =48896a(8) =196096a(9) =785408a(10) =3143680a(11) =12578816a(12) =50323456a(13) =201310208a(14) =805273600a(15) =3221159936a(16) =12884770816a(17) =51539345408a(18) =206157905920a(19) =824632672256