1889 at Eulerian Eulerian constant, the value of 1 + 1/ 2 + 1/ 3 + … + 1/ n − 1 − 1/ n + 1 + 1/ n + 2 + … + 1/ n2 − 1 − 1/ 3n2 − 1/ 10n4 − 1/ 126n6, where n is infinite. It is 0.57721566490153286060+.
1991 C. B. Boyer & U. C. Merzbach (ed. 2) xxi. 442 The so-called ‘Eulerian constant’, often represented by the Greek letter γ, is..a well-known number that has been calculated to hundreds of decimal places, of which the first ten are 0.5772156649.