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Curious congruences for cyclotomic polynomials

Number Theory 2022-10-31 v6 Combinatorics

Abstract

Let Φn(k)(x)\Phi_n^{(k)}(x) be the kk-th derivative of nn-th cyclotomic polynomial. Extending a work of D.~H.~Lehmer, we show some curious congruences: 2Φn(3)(1)2\Phi^{(3)}_n(1) is divisible by ϕ(n)2\phi(n)-2 and Φn(2k+1)(1)\Phi^{(2k+1)}_n(1) is divisible by ϕ(n)2k\phi(n)-2k for k2k\ge 2. The congruence stems from a general property of self-reciprocal polynomials.

Keywords

Cite

@article{arxiv.2204.11267,
  title  = {Curious congruences for cyclotomic polynomials},
  author = {Shigeki Akiyama and Hajime Kaneko},
  journal= {arXiv preprint arXiv:2204.11267},
  year   = {2022}
}

Comments

See remarks we recieved afterwards in the appendix. To appear in Research in Number Theory

R2 v1 2026-06-24T10:57:02.637Z