Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, up, up.
A177605
Number of permutations of 3 copies of 1..n avoiding adjacent step pattern up, up, up, up.
Terms
- a(0) =1a(1) =1a(2) =20a(3) =1680a(4) =369600a(5) =166923119a(6) =134612399509
External references
- oeis: A177605