a(n) = Sum_{k=0..n} (-1)^(n+k)*A111516(n,k).

Terms

a(0) =1a(1) =0a(2) =2a(3) =12a(4) =50a(5) =280a(6) =1442a(7) =7812a(8) =42338a(9) =232176a(10) =1280642a(11) =7103932a(12) =39579410a(13) =221340808a(14) =1241708834a(15) =6984796852a(16) =39382895810a(17) =222512915680