A class of Littlewood polynomials that are not $L^\alpha$-flat

Abstract

We exhibit a class of Littlewood polynomials that are not $L^\alpha$-flat for any $\alpha \geq 0$. Indeed, it is shown that the sequence of Littlewood polynomials is not $L^\alpha$-flat, $\alpha \geq 0$, when the frequency of $-1$ is not in the interval $]\frac14,\frac34[$. We further obtain a generalization of Jensen-Jensen-Hoholdt's result by establishing that the sequence of Littlewood polynomials is not $L^\alpha$-flat for any $\alpha> 2$ if the frequency of $-1$ is not $\frac12$. Finally, we prove that the sequence of palindromic Littlewood polynomials with even degrees are not $L^\alpha$-flat for any $\alpha \geq 0$.