English

Congruences involving binomial coefficients and Ap\'ery-like numbers

Number Theory 2020-05-12 v7 Combinatorics

Abstract

For n=0,1,2,n=0,1,2,\ldots let Wn=k=0[n/3](2kk)(3kk)(n3k)(3)n3kW_n=\sum_{k=0}^{[n/3]}\binom{2k}k \binom{3k}k\binom n{3k}(-3)^{n-3k}, where [x][x] is the greatest integer not exceeding xx. Then {Wn}\{W_n\} is an Ap\'ery-like sequence. In this paper we deduce many congruences involving {Wn}\{W_n\}, in particular we determine k=0p1(2kk)Wkmk(modp)\sum_{k=0}^{p-1}\binom{2k}k\frac{W_k}{m^k}\pmod p for m=640332,5292,972,108,44,27,12,8,54,243m=-640332,-5292,-972,-108,-44,-27,-12,8,54,243 by using binary quadratic forms, where p>3p>3 is a prime. We also prove several congruences for generalized Ap\'ery-like numbers, and pose 29 challenging conjectures on congruences involving binomial coefficients and Ap\'ery-like numbers.

Keywords

Cite

@article{arxiv.1803.10051,
  title  = {Congruences involving binomial coefficients and Ap\'ery-like numbers},
  author = {Zhi-Hong Sun},
  journal= {arXiv preprint arXiv:1803.10051},
  year   = {2020}
}

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28 pages