Chocolate numbers.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =24a(5) =56a(6) =120a(7) =720a(8) =1712a(9) =5040a(10) =9408a(11) =40320a(12) =92800a(13) =362880a(14) =3628800a(15) =4948992a(16) =7918592a(17) =39916800a(18) =479001600a(19) =984237056a(20) =6085088256a(21) =6227020800a(22) =63352393728a(23) =87178291200a(24) =168662855680