English

Legendre symbols related to certain determinants

Number Theory 2023-05-22 v3

Abstract

Let pp be an odd prime. For b,cZb,c\in\mathbb Z, Sun introduced the determinant Dp(b,c)=(i2+bij+cj2)p21i,jp1,D_p(b,c)=\left|(i^2+bij+cj^2)^{p-2}\right|_{1\leqslant i,j \leqslant p-1}, and investigated the Legendre symbol (Dp(b,c)p)(\frac{D_p(b,c)}p). Recently Wu, She and Ni proved that (Dp(1,1)p)=(2p)(\frac{D_p(1,1)}p)=(\frac {-2}p) if p2(mod3)p\equiv2\pmod 3, which confirms a previous conjecture of Sun. In this paper we determine (Dp(1,1)p)(\frac{D_p(1,1)}p) in the case p1(mod3)p\equiv1\pmod3. Sun proved that Dp(2,2)0(modp)D_p(2,2)\equiv0\pmod p if p3(mod4)p\equiv3\pmod4, in contrast we prove that (Dp(2,2)p)=1(\frac{D_p(2,2)}p)=1 if p1(mod8)p\equiv1\pmod8, and (Dp(2,2)p)=0(\frac{D_p(2,2)}p)=0 if p5(mod8)p\equiv5\pmod8. Our tools include generalized trinomial coefficients and Lucas sequences.

Keywords

Cite

@article{arxiv.2210.14741,
  title  = {Legendre symbols related to certain determinants},
  author = {Xin-Qi Luo and Zhi-Wei Sun},
  journal= {arXiv preprint arXiv:2210.14741},
  year   = {2023}
}

Comments

20 pages,

R2 v1 2026-06-28T04:33:38.514Z