English

Some Nice Sums are Almost as Nice if you turn them Upside Down

Combinatorics 2009-09-12 v2 Number Theory

Abstract

We represent the sums k=0n1(nk)2\sum_{k=0}^{n-1}{n \choose k}^{-2}, k=0m(mk)1(ank)1\sum_{k=0}^m{m\choose k}^{-1}{a\choose n-k}^{-1}, k=0n1qk(k1)[nk]q\sum_{k=0}^{n-1}\frac{q^{-k(k-1)}}{{\genfrac{[}{]}{0pt}{}{n}{k}}_q}, and the sum of the reciprocals of the summands in Dixon's identity, each as a product of an {\it indefinite hypergeometric sum} times a (closed form) {\it hypergeometric sequence}

Keywords

Cite

@article{arxiv.0907.3174,
  title  = {Some Nice Sums are Almost as Nice if you turn them Upside Down},
  author = {Moa Apagodu and Doron Zeilberger},
  journal= {arXiv preprint arXiv:0907.3174},
  year   = {2009}
}

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6 pages