Published online by Cambridge University Press: 17 April 2009
The formula of [E.] Meissel [Math. Ann. 2 (1870), 636–642] is generalized to arbitrary arithmetic progressions. Meissel's formula is applicable not only to computation of π(x) for large x (recently x = 1013), but also is a sieve technique (see MR36#2548), useful for studying the subtle effect of primes less then or equal to x1/2 on the behavior of primes less than or equal to x. The same is true of the generalized Meissel, with the added advantage that the behavior of primes less than or equal to x can be studied in arbitrary progressions.