Total number of inversions over all involutions of length n.

Terms

a(0) =0a(1) =0a(2) =1a(3) =5a(4) =26a(5) =110a(6) =490a(7) =2086a(8) =9240a(9) =40776a(10) =185820a(11) =855580a(12) =4048616a(13) =19455800a(14) =95773496a(15) =479581480a(16) =2454041920a(17) =12776826816a(18) =67849286160a(19) =366455145936