a(n) = number of possible pairs of descent sets of a permutation of 1,2,...,n and its inverse.
A380394
a(n) = number of possible pairs of descent sets of a permutation of 1,2,...,n and its inverse.
Terms
- a(0) =1a(1) =1a(2) =2a(3) =6a(4) =22a(5) =94a(6) =426a(7) =1938a(8) =8724a(9) =38724a(10) =169438a(11) =731390a(12) =3119052a(13) =13162228
External references
- oeis: A380394