The number of cycles over all even permutations of {1,2,...,n}.

A226170

The number of cycles over all even permutations of {1,2,...,n}.

Terms

    a(0) =0a(1) =1a(2) =2a(3) =5a(4) =26a(5) =134a(6) =894a(7) =6474a(8) =55152a(9) =510768a(10) =5334480a(11) =60090480a(12) =745035840a(13) =9881421120a(14) =141972324480

External references