Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k adjacent pairs of the form (odd,even) (0<=k<=floor(n/2)).

A145891

Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k adjacent pairs of the form (odd,even) (0<=k<=floor(n/2)).

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =4a(7) =16a(8) =4a(9) =12a(10) =72a(11) =36a(12) =36a(13) =324a(14) =324a(15) =36a(16) =144a(17) =1728a(18) =2592a(19) =576a(20) =576a(21) =9216a(22) =20736a(23) =9216a(24) =576a(25) =2880a(26) =57600a(27) =172800a(28) =115200a(29) =14400

External references