A239373 Words of length n over the alphabet {0,...,n-1} that avoid the pattern 1213.
1, 1, 4, 27, 252, 2935, 40330, 632408
Offset: 0
Crossrefs
Cf. A239295.
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.