a(n) = Sum_{k=0..n} 4^k*A111146(n,k).

Terms

a(0) =1a(1) =4a(2) =32a(3) =272a(4) =2400a(5) =21792a(6) =203008a(7) =1940224a(8) =19065344a(9) =193410560a(10) =2038078464a(11) =22490167296a(12) =262429339648