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Two congruences concerning Ap\'{e}ry numbers

Number Theory 2020-06-30 v1 Combinatorics

Abstract

Let nn be a nonnegative integer. The nn-th Ap\'{e}ry number is defined by An:=k=0n(n+kk)2(nk)2. A_n:=\sum_{k=0}^n\binom{n+k}{k}^2\binom{n}{k}^2. Z.-W. Sun ever investigated the congruence properties of Ap\'{e}ry numbers and posed some conjectures. For example, Sun conjectured that for any prime p7p\geq7 k=0p1(2k+1)Akp72p2Hp1(modp6) \sum_{k=0}^{p-1}(2k+1)A_k\equiv p-\frac{7}{2}p^2H_{p-1}\pmod{p^6} and for any prime p5p\geq5 k=0p1(2k+1)3Akp3+4p4Hp1+65p8Bp5(modp9), \sum_{k=0}^{p-1}(2k+1)^3A_k\equiv p^3+4p^4H_{p-1}+\frac{6}{5}p^8B_{p-5}\pmod{p^9}, where Hn=k=1n1/kH_n=\sum_{k=1}^n1/k denotes the nn-th harmonic number and B0,B1,B_0,B_1,\ldots are the well-known Bernoulli numbers. In this paper we shall confirm these two conjectures.

Keywords

Cite

@article{arxiv.1909.08983,
  title  = {Two congruences concerning Ap\'{e}ry numbers},
  author = {Chen Wang},
  journal= {arXiv preprint arXiv:1909.08983},
  year   = {2020}
}

Comments

14 pages

R2 v1 2026-06-23T11:20:15.336Z