{ "id": "0807.2629", "version": "v1", "published": "2008-07-16T19:06:14.000Z", "updated": "2008-07-16T19:06:14.000Z", "title": "Divisibility by 2 and 3 of certain Stirling numbers", "authors": [ "Donald M Davis" ], "comment": "35 pages, submitted", "categories": [ "math.NT", "math.AT" ], "abstract": "The numbers e_p(k,n) defined as min(nu_p(S(k,j)j!): j >= n) appear frequently in algebraic topology. Here S(k,j) is the Stirling number of the second kind, and nu_p(-) the exponent of p. The author and Sun proved that if L is sufficiently large, then e_p((p-1)p^L + n -1, n) >= n-1+nu_p([n/p]!). In this paper, we determine the set of integers n for which equality holds in this inequality when p=2 and 3. The condition is roughly that, in the base-p expansion of n, the sum of two consecutive digits must always be less than p.", "revisions": [ { "version": "v1", "updated": "2008-07-16T19:06:14.000Z" } ], "analyses": { "subjects": [ "11B73", "55Q52" ], "keywords": [ "stirling number", "divisibility", "algebraic topology", "second kind", "equality holds" ], "note": { "typesetting": "TeX", "pages": 35, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2008arXiv0807.2629D" } } }