{"title":"对leonetti和luca定理的改进","authors":"Tran Nguyen Thanh Danh, Hoang Tuan Dung, Pham Viet Hung, Nguyen Dinh Kien, Nguyen AN Thinh, Khuc Dinh Toan, N. X. Tho","doi":"10.1017/s0004972723000862","DOIUrl":null,"url":null,"abstract":"\n\t <jats:p>Leonetti and Luca [‘On the iterates of the shifted Euler’s function’, <jats:italic>Bull. Aust. Math. Soc.</jats:italic>, to appear] have shown that the integer sequence <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline1.png\" />\n\t\t<jats:tex-math>\n$(x_n)_{n\\geq 1}$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula> defined by <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline2.png\" />\n\t\t<jats:tex-math>\n$x_{n+2}=\\phi (x_{n+1})+\\phi (x_{n})+k$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>, where <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline3.png\" />\n\t\t<jats:tex-math>\n$x_1,x_2\\geq 1$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>, <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline4.png\" />\n\t\t<jats:tex-math>\n$k\\geq 0$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula> and <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline5.png\" />\n\t\t<jats:tex-math>\n$2 \\mid k$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>, is bounded by <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline6.png\" />\n\t\t<jats:tex-math>\n$4^{X^{3^{k+1}}}$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>, where <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline7.png\" />\n\t\t<jats:tex-math>\n$X=(3x_1+5x_2+7k)/2$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>. We improve this result by showing that the sequence <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline8.png\" />\n\t\t<jats:tex-math>\n$(x_n)$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula> is bounded by <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline9.png\" />\n\t\t<jats:tex-math>\n$2^{2X^2+X-3}$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>, where <jats:inline-formula>\n\t <jats:alternatives>\n\t\t<jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0004972723000862_inline10.png\" />\n\t\t<jats:tex-math>\n$X=x_1+x_2+2k$\n</jats:tex-math>\n\t </jats:alternatives>\n\t </jats:inline-formula>.</jats:p>","PeriodicalId":50720,"journal":{"name":"Bulletin of the Australian Mathematical Society","volume":" ","pages":""},"PeriodicalIF":0.6000,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"AN IMPROVEMENT TO A THEOREM OF LEONETTI AND LUCA\",\"authors\":\"Tran Nguyen Thanh Danh, Hoang Tuan Dung, Pham Viet Hung, Nguyen Dinh Kien, Nguyen AN Thinh, Khuc Dinh Toan, N. X. Tho\",\"doi\":\"10.1017/s0004972723000862\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\n\\t <jats:p>Leonetti and Luca [‘On the iterates of the shifted Euler’s function’, <jats:italic>Bull. Aust. Math. Soc.</jats:italic>, to appear] have shown that the integer sequence <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline1.png\\\" />\\n\\t\\t<jats:tex-math>\\n$(x_n)_{n\\\\geq 1}$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula> defined by <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline2.png\\\" />\\n\\t\\t<jats:tex-math>\\n$x_{n+2}=\\\\phi (x_{n+1})+\\\\phi (x_{n})+k$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>, where <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline3.png\\\" />\\n\\t\\t<jats:tex-math>\\n$x_1,x_2\\\\geq 1$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>, <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline4.png\\\" />\\n\\t\\t<jats:tex-math>\\n$k\\\\geq 0$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula> and <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline5.png\\\" />\\n\\t\\t<jats:tex-math>\\n$2 \\\\mid k$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>, is bounded by <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline6.png\\\" />\\n\\t\\t<jats:tex-math>\\n$4^{X^{3^{k+1}}}$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>, where <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline7.png\\\" />\\n\\t\\t<jats:tex-math>\\n$X=(3x_1+5x_2+7k)/2$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>. We improve this result by showing that the sequence <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline8.png\\\" />\\n\\t\\t<jats:tex-math>\\n$(x_n)$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula> is bounded by <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline9.png\\\" />\\n\\t\\t<jats:tex-math>\\n$2^{2X^2+X-3}$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>, where <jats:inline-formula>\\n\\t <jats:alternatives>\\n\\t\\t<jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0004972723000862_inline10.png\\\" />\\n\\t\\t<jats:tex-math>\\n$X=x_1+x_2+2k$\\n</jats:tex-math>\\n\\t </jats:alternatives>\\n\\t </jats:inline-formula>.</jats:p>\",\"PeriodicalId\":50720,\"journal\":{\"name\":\"Bulletin of the Australian Mathematical Society\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":0.6000,\"publicationDate\":\"2023-09-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Bulletin of the Australian Mathematical Society\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1017/s0004972723000862\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of the Australian Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1017/s0004972723000862","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
Leonetti and Luca [‘On the iterates of the shifted Euler’s function’, Bull. Aust. Math. Soc., to appear] have shown that the integer sequence
$(x_n)_{n\geq 1}$
defined by
$x_{n+2}=\phi (x_{n+1})+\phi (x_{n})+k$
, where
$x_1,x_2\geq 1$
,
$k\geq 0$
and
$2 \mid k$
, is bounded by
$4^{X^{3^{k+1}}}$
, where
$X=(3x_1+5x_2+7k)/2$
. We improve this result by showing that the sequence
$(x_n)$
is bounded by
$2^{2X^2+X-3}$
, where
$X=x_1+x_2+2k$
.
期刊介绍:
Bulletin of the Australian Mathematical Society aims at quick publication of original research in all branches of mathematics. Papers are accepted only after peer review but editorial decisions on acceptance or otherwise are taken quickly, normally within a month of receipt of the paper. The Bulletin concentrates on presenting new and interesting results in a clear and attractive way.
Published Bi-monthly
Published for the Australian Mathematical Society