a(n) = A027144(2n-1, n-2).

Terms

a(0) =1a(1) =10a(2) =42a(3) =352a(4) =1360a(5) =11616a(6) =43680a(7) =381952a(8) =1416960a(9) =12620800a(10) =46441472a(11) =419512320a(12) =1535352832a(13) =14021353472a(14) =51117465600a(15) =470886645760