A177671 Number of permutations of 4 copies of 1..n avoiding adjacent step pattern up, up, down, down, down, down.
1, 1, 70, 34650, 63063000, 304935162828, 3227357965784040, 65712161060921061615
Offset: 0
Keywords
Crossrefs
Cf. A014608.
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.