{ "id": "0709.4031", "version": "v2", "published": "2007-09-26T17:28:30.000Z", "updated": "2011-03-27T21:39:35.000Z", "title": "Infinite products with strongly $B$-multiplicative exponents", "authors": [ "Jean-Paul Allouche", "Jonathan Sondow" ], "comment": "Updated [14] and journal reference", "journal": "Annales Univ. Sci. Budapest. Sect. Comput. 28 (2008) 35-53. Errata 32 (2010) 253", "categories": [ "math.NT" ], "abstract": "Let $N_{1,B}(n)$ denote the number of ones in the $B$-ary expansion of an integer $n$. Woods introduced the infinite product $P :=\\prod_{n \\geq 0} (\\frac{2n+1}{2n+2})^{(-1)^{N_{1,2}(n)}}$ and Robbins proved that $P = 1/\\sqrt{2}$. Related products were studied by several authors. We show that a trick for proving that $P^2 = 1/2$ (knowing that $P$ converges) can be extended to evaluating new products with (generalized) strongly $B$-multiplicative exponents. A simple example is $$ \\prod_{n \\geq 0} (\\frac{Bn+1}{Bn+2})^{(-1)^{N_{1,B}(n)}} = \\frac{1}{\\sqrt B}. $$", "revisions": [ { "version": "v2", "updated": "2011-03-27T21:39:35.000Z" } ], "analyses": { "subjects": [ "11A63", "11Y60" ], "keywords": [ "infinite product", "multiplicative exponents", "ary expansion", "simple example", "related products" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007arXiv0709.4031A" } } }