Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, down, up, down.
A177567
Number of permutations of 2 copies of 1..n avoiding adjacent step pattern up, down, down, up, down.
Terms
- a(0) =1a(1) =6a(2) =88a(3) =2304a(4) =95440a(5) =5730914a(6) =471168554a(7) =50843909070
External references
- oeis: A177567