Number of adjacent pairs of form (even,odd) among all permutations of {1,2,...,n}. Also, number of adjacent pairs of form (odd,even).

A077613

Number of adjacent pairs of form (even,odd) among all permutations of {1,2,...,n}. Also, number of adjacent pairs of form (odd,even).

Terms

    a(0) =0a(1) =1a(2) =4a(3) =24a(4) =144a(5) =1080a(6) =8640a(7) =80640a(8) =806400a(9) =9072000a(10) =108864000a(11) =1437004800a(12) =20118067200a(13) =305124019200

External references