Number of ordered pairs (p,q) of permutations of [n] with equal up-down signatures and p(1)=q(1)=2.
A262479
Number of ordered pairs (p,q) of permutations of [n] with equal up-down signatures and p(1)=q(1)=2.
Terms
- a(0) =1a(1) =2a(2) =8a(3) =68a(4) =952a(5) =19312a(6) =533544a(7) =19209584a(8) =873274112a(9) =48904686848
External references
- oeis: A262479