Lehmer¶
An \(n \times n\) Lehmer matrix is a symmetric positive-definite matrix whose upper-triangle is defined via the equation
\[A(i,j) = \frac{i+1}{j+1},\;\;\; i \le j.\]
The inverse of the Lehmer matrix is known to be symmetric tridiagonal (with positive eigenvalues), and the condition number is known to be bounded by the relationship
\[n \le \text{cond}(A) \le 4 n^2.\]