The Hafner-Sarnak-McCurley constant $\omega$ is the limit of the probabilities $D(n)$ as $n \to \infty$ that the determinants of two random $n\times n$ matrices with integral coefficients have coprime determinants.
Formulas
(1)
$\omega = \prod_p \big(1- \big(1 - \prod_{j=1}^\infty (1-p^{-j})\big)^2 \big)$, where the outer product ranges over all primes $p$.
L. Hafner, P. Sarnak and K. McCurley, "Relatively prime values of polynomials", In A Tribute to Emil Grosswald: Number Theory and Related Analysis, Contemporary Mathematics (1993), M. Knopp and M. Sheigorn, Editors, vol. 143.
Transcribed from the literature rather than computed here, and not checked against an independent computation, which is the difference between this table and the twin prime constant beside it.
