English

On finding all positive integers $a,b$ such that $b\pm a$ and $ab$ are palindromic

History and Overview 2019-01-15 v2

Abstract

It is proven that the only integer solutions (a,b)(a,b) such that a+ba+b and abab are palindromic are (2,510k3)(2,5\cdot 10^k-3), (3,24)(3,24) and (9,9)(9,9), and in a similar fashion, bab-a and abab are only palindromic at (a,b)=(3,147104(k+1)+5247i=0k104i)(a,b)=(3,147\cdot 10^{4(k+1)}+5247\sum_{i=0}^k10^{4i}), (3,161247104k+7+5247i=0k104i+3+387)(3,161\,247\cdot 10^{4k+7}+5247\sum_{i=0}^k10^{4i+3}+387), (3,147)(3,147) and (3,161247387)(3,161\,247\,387) for k=0,1,2,k=0,1,2,\cdots. Note aba\le b without loss of generality.

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Cite

@article{arxiv.1812.08807,
  title  = {On finding all positive integers $a,b$ such that $b\pm a$ and $ab$ are palindromic},
  author = {Wang Pok Lo and Yuval Paz},
  journal= {arXiv preprint arXiv:1812.08807},
  year   = {2019}
}

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8 pages