Triangle read by rows: T(n,k) is the number of even permutations of {1,2,...,n} with no fixed points and having k excedances (n>=1; k>=1).

A145881

Triangle read by rows: T(n,k) is the number of even permutations of {1,2,...,n} with no fixed points and having k excedances (n>=1; k>=1).

Terms

    a(0) =0a(1) =0a(2) =1a(3) =1a(4) =0a(5) =3a(6) =0a(7) =1a(8) =11a(9) =11a(10) =1a(11) =0a(12) =25a(13) =80a(14) =25a(15) =0a(16) =1a(17) =57a(18) =407a(19) =407a(20) =57a(21) =1a(22) =0a(23) =119a(24) =1680a(25) =3815a(26) =1680a(27) =119a(28) =0a(29) =1

External references