Triangle T(n,k), 1 <= k <= n, read by rows: T(n,k) is the number of permutations of the set {2,4,6,...,2n} with k excedances. Equivalently, T(n,k) is the number of permutations in the symmetric group S_n having k multiplicative 2-excedances.
A136715
Triangle T(n,k), 1 <= k <= n, read by rows: T(n,k) is the number of permutations of the set {2,4,6,...,2n} with k excedances. Equivalently, T(n,k) is the number of permutations in the symmetric group S_n having k multiplicative 2-excedances.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =0a(4) =4a(5) =2a(6) =0a(7) =4a(8) =16a(9) =4a(10) =0a(11) =0a(12) =36a(13) =72a(14) =12a(15) =0a(16) =0a(17) =36a(18) =324a(19) =324a(20) =36a(21) =0a(22) =0a(23) =0a(24) =576a(25) =2592a(26) =1728a(27) =144a(28) =0a(29) =0
External references
- oeis: A136715