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

Terms

a(0) =1a(1) =12a(2) =80a(3) =448a(4) =2304a(5) =11264a(6) =53248a(7) =245760a(8) =1114112a(9) =4980736a(10) =22020096a(11) =96468992a(12) =419430400a(13) =1811939328a(14) =7784628224a(15) =33285996544a(16) =141733920768a(17) =601295421440