Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down.
A177638
Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, down, down.
Terms
- a(0) =1a(1) =70a(2) =25446a(3) =29416791a(4) =83400344760
External references
- oeis: A177638