Cardinality of the permutation (k, k-1, ..., 2, 1)(n, n-1, ..., k+1) in an exchange shuffle applied in all n^n possible ways to (1,2,...,n).
A013560
Cardinality of the permutation (k, k-1, ..., 2, 1)(n, n-1, ..., k+1) in an exchange shuffle applied in all n^n possible ways to (1,2,...,n).
Terms
- a(0) =1a(1) =2a(2) =5a(3) =15a(4) =47a(5) =159a(6) =543a(7) =1931a(8) =6879a(9) =25118a(10) =91693
External references
- oeis: A013560