{ "id": "2201.08168", "version": "v1", "published": "2022-01-20T13:35:01.000Z", "updated": "2022-01-20T13:35:01.000Z", "title": "Pattern-avoidance and Fuss-Catalan numbers", "authors": [ "Per Alexandersson", "Samuel Asefa Fufa", "Frether Getachew", "Dun Qiu" ], "comment": "23 pages", "categories": [ "math.CO" ], "abstract": "We study a subset of permutations, where entries are restricted to having the same remainder as the index, modulo some integer $k \\geq 2$. We show that when also imposing the classical 132- or 213-avoidance restriction on the permutations, we recover the Fuss--Catalan numbers. Surprisingly, an analogous statement also holds when we impose the mod $k$ restriction on a Catalan family of subexcedant functions. Finally, we completely enumerate all combinations of mod-$k$-alternating permutations, avoiding two patterns of length 3. This is analogous to the systematic study by Simion and Schmidt, of permutations avoiding two patterns of length 3.", "revisions": [ { "version": "v1", "updated": "2022-01-20T13:35:01.000Z" } ], "analyses": { "subjects": [ "05A05", "05A19" ], "keywords": [ "fuss-catalan numbers", "pattern-avoidance", "systematic study", "subexcedant functions", "restriction" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }