To Örebro University

An amended version of Proposition 3.6 of [Fasi and Negri Porzio, Electron. J. Linear Algebra 36:352{366, 2020] is presented. The result shows that the set of possible determinants of upper Hessenberg matrices with ones on the subdiagonal and elements in the upper triangular part drawn from the set {-1, 1} is {2k vertical bar k is an element of <-2(n-2), 2(n-2)>}, instead of {2k vertical bar k is an element of <-n + 1, n - 1 >} as previously stated. This does not affect the main results of the article being corrected and shows that Conjecture 20 in the Characteristic Polynomial Database is true.