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

A145892

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

Terms

    a(0) =1a(1) =1a(2) =2a(3) =6a(4) =12a(5) =12a(6) =72a(7) =48a(8) =144a(9) =432a(10) =144a(11) =1440a(12) =2880a(13) =720a(14) =2880a(15) =17280a(16) =17280a(17) =2880a(18) =43200a(19) =172800a(20) =129600a(21) =17280a(22) =86400a(23) =864000a(24) =1728000a(25) =864000a(26) =86400a(27) =1814400a(28) =12096000a(29) =18144000

External references