A beautiful approximation to the Euler-Mascheroni constant γ is given by π/(2e) = 0.577864... (OEIS A086056; E. W. Weisstein, Apr. 18, 2006), which is good to three decimal digits. In 1982-1983, Odena gave the strange approximation (0.111111)^(1/4) = 0.57735..., which is effectively 3^(-1/2) = 0.57735... (Munroe 2012).

almost integer | Euler-Mascheroni constant