"The" Smarandache constant is the smallest solution to the generalized Andrica's conjecture, x≈0.567148 (OEIS A038458).
The first Smarandache constant is defined as
S_1 congruent sum_(n = 2)^∞ 1/([μ(n)]!) = 1.09317...
(OEIS A048799), where μ(n) is the Smarandache function. Cojocaru and Cojocaru (1996a) prove that S_1 exists and is bounded by 0.717