{ "id": "2106.14755", "version": "v1", "published": "2021-06-28T14:30:08.000Z", "updated": "2021-06-28T14:30:08.000Z", "title": "Counting Divisions of a $2\\times n$ Rectangular Grid", "authors": [ "Jacob Brown" ], "comment": "9 pages, 5 figures", "categories": [ "math.CO" ], "abstract": "Consider a $2\\times n$ rectangular grid composed of $1\\times 1$ squares. Cutting only along the edges between squares, how many ways are there to divide the board into $k$ pieces? Building off the work of Durham and Richmond, who found the closed-form solutions for the number of divisions into 2 and 3 pieces, we prove a recursive relationship that counts the number of divisions of the board into $k$ pieces. Using this recursion, we obtain closed-form solutions for the number of divisions for $k=4$ and $k=5$ using fitting techniques on data generated from the recursion. Furthermore, we show that the closed-form solution for any fixed $k$ must be a polynomial on $n$ with degree $2k-2$.", "revisions": [ { "version": "v1", "updated": "2021-06-28T14:30:08.000Z" } ], "analyses": { "subjects": [ "05A18" ], "keywords": [ "rectangular grid", "counting divisions", "closed-form solution", "recursive relationship", "fitting techniques" ], "note": { "typesetting": "TeX", "pages": 9, "language": "en", "license": "arXiv", "status": "editable" } } }