On the Eigenvalues of Redheffer’s Matrix, I

Let A_n be the n × n matrix (a_ij ) introduced by Redheffer [1977] in which a_ij is given for i = 1, …n; j = 1…,n, by (1) a i j   =   { 1 when   i   |   j     or     j   =   1 , 0 otherwise . https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203747018/bef25d74-ef02-4914-ac4f-27ec89fc30ac/content/eq2294.tif"/>