Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, down.
A177602
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, down, up, down.
Terms
- a(0) =1a(1) =18a(2) =1200a(3) =196544a(4) =64274760a(5) =36903349792
External references
- oeis: A177602