3 problems

Let $\mathcal{C}_d$ be the class of $d$-ary sequences rich in palindromes. For each $n\in\mathbb{N}$, let $\mathbf{u}_n$ denote the sequence defined in the paper by the correspondi…

Let $m\in\mathbb{N}$, and let $A\in\mathbb{N}^{\mathbb{N}_0}$ be an $m$-palindromic sequence that is not eventually periodic. Let $d_m([A])$ denote its $m$-palindromic density. For…

Hof–Knill–Simon conjecture. ${\bf u}$ is palindromic if and only if there exists a morphism $\varphi\neq\operatorname{Id}$ such that