a(n) = A192384(n)/2.

Terms

a(0) =0a(1) =1a(2) =2a(3) =12a(4) =36a(5) =156a(6) =544a(7) =2144a(8) =7872a(9) =30096a(10) =112416a(11) =425536a(12) =1598528a(13) =6031296a(14) =22699008a(15) =85552128a(16) =322177024a(17) =1213849856a(18) =4572111360a(19) =17224104960a(20) =64880993280a(21) =244410981376a(22) =920685043712