{ "id": "1607.04764", "version": "v1", "published": "2016-07-16T16:49:18.000Z", "updated": "2016-07-16T16:49:18.000Z", "title": "On the representations of a positive integer by certain classes of quadratic forms in eight variables", "authors": [ "B. Ramakrishnan", "Brundaban Sahu", "Anup Kumar Singh" ], "comment": "18 pages, 7 tables. arXiv admin note: substantial text overlap with arXiv:1607.03809", "categories": [ "math.NT" ], "abstract": "In this paper we use the theory of modular forms to find formulas for the number of representations of a positive integer by certain class of quadratic forms in eight variables, viz., forms of the form $a_1x_1^2 + a_2 x_2^2 + a_3 x_3^2 + a_4 x_4^2 + b_1(x_5^2+x_5x_6 + x_6^2) + b_2(x_7^2+x_7x_8 + x_8^2)$, where $a_1\\le a_2\\le a_3\\le a_4$, $b_1\\le b_2$ and $a_i$'s $\\in \\{1,2,3\\}$, $b_i$'s $\\in \\{1,2,4\\}$. We also determine formulas for the number of representations of a positive integer by the quadratic forms $(x_1^2+x_1x_2+x_2^2) + c_1(x_3^2+x_3x_4+x_4^2) + c_2(x_5^2+x_5x_6+x_6^2) + c_3(x_7^2+x_7x_8+x_8^2)$, where $c_1,c_2,c_3\\in \\{1,2,4,8\\}$, $c_1\\le c_2\\le c_3$.", "revisions": [ { "version": "v1", "updated": "2016-07-16T16:49:18.000Z" } ], "analyses": { "subjects": [ "11F25", "11A25", "11F11" ], "keywords": [ "quadratic forms", "positive integer", "representations", "determine formulas" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }