English

$\phi$-Thue-Morse sequences and infinite products

Combinatorics 2020-06-11 v1 Number Theory

Abstract

In this article we introduce a new approach to compute infinite products defined by automatic sequences involving the Thue-Morse sequence. As examples, for any positive integers qq and rr such that 0rq10 \leq r \leq q-1, we find infinitely many couples of rational functions R(x)R(x) and S(n)S(n) such that n=0R(n)1+an2S(n)1an2=2cos(2r+12qπ),\prod_{n=0}^{\infty}R(n)^{\frac{1+a_n}{2}}S(n)^{\frac{1-a_n}{2}}=2cos(\frac{2r+1}{2q}\pi), where (an)nN(a_n)_{n \in \mathbf{N}} is the Thue-Morse sequence beginning with a0=1,a1=1a_0=1,a_1= -1.

Keywords

Cite

@article{arxiv.2006.04909,
  title  = {$\phi$-Thue-Morse sequences and infinite products},
  author = {Shuo Li},
  journal= {arXiv preprint arXiv:2006.04909},
  year   = {2020}
}
R2 v1 2026-06-23T16:09:42.088Z