Number of permutations of [n] having the maximal possible number of pairs of integers i<j in [n] such that their cycle minima have opposite sorting order.

A381531

Number of permutations of [n] having the maximal possible number of pairs of integers i<j in [n] such that their cycle minima have opposite sorting order.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =1a(4) =4a(5) =5a(6) =2a(7) =14a(8) =34a(9) =34a(10) =12a(11) =132a(12) =540a(13) =1020a(14) =888a(15) =288a(16) =4608a(17) =28800a(18) =89280a(19) =143712a(20) =113472a(21) =34560a(22) =760320a(23) =6773760a(24) =31449600a(25) =81527040a(26) =117089280a(27) =85847040a(28) =24883200a(29) =721612800

External references