PRIMECOUNT(1) PRIMECOUNT(1) (NAME) primecount - (SYNOPSIS) primecount x [] (DESCRIPTION) x ( 10^31) . primecount (Xavier Gourdon) O(x^(2/3) / log^2 x) O(x^(2/3) * log^3 x) . primecount (CPU) . (OPTIONS) -d, --deleglise-rivat - (Deleglise-Rivat). --double-check pi(x) () . primecount : pi(x) ( ) . -g, --gourdon ( ). -l, --legendre (Legendre). --lehmer (Lehmer). --lmo -- (Lagarias-Miller-Odlyzko). -m, --meissel (Meissel). --Li pi(x) : Li(x) Li(x) = li(x) - li(2). --Li-inverse n- : Li^-1(x). -n, --nth-prime n- . -p, --primesieve (sieve of Eratosthenes). --phi X A phi(x, a) <= x a . -R, --RiemannR pi(x) R : R(x). --RiemannR-inverse n- R : R^-1(x). --RiemannR-psi pi(x) R R(psi(x)). --RiemannR psi(x) R(psi(x)) . pi(x) R(x) . --RiemannR-psi-inverse n- R(psi(x)). --RiemannR-inverse R(x) psi . n- R^-1(x) . -s, --status[=NUM] 1%, 2%, 3%, ... NUM : --status=1 99.9% . --test . --time . -t, --threads=NUM 1 <= NUM <= (CPU). primecount . -v, --version (). -h, --help . - (ADVANCED OPTIONS FOR THE DELEGLISE-RIVAT ALGORITHM) --P2 . --S1 (ordinary leaves). --S2-trivial (trivial special leaves). --S2-easy (easy special leaves). --S2-hard (hard special leaves). (Tuning factor) (alpha) S2_easy S2_hard . S2_hard S2_easy . primecount . pi(x) . pi(x) . pi(x) pi(x) . -a, --alpha=NUM : y = x^(1/3) * alpha 1 <= alpha <= x^(1/6). (ADVANCED OPTIONS FOR XAVIER GOURDON'S ALGORITHM) --AC A + C. --B B. --D D. --Phi0 Phi0. --Sigma Sigma. (Tuning factors) alpha_y alpha_z A B C D . alpha_y alpha_z B A C D . primecount alpha_y alpha_z . alpha_y alpha_z pi(x) . pi(x) alpha_y / alpha_z . pi(x) pi(x) . --alpha-y=NUM alpha_y: y = x^(1/3) * alpha_y 1 <= alpha_y <= x^(1/6). --alpha-z=NUM alpha_z: z = y * alpha_z 1 <= alpha_z <= x^(1/6). PI(X) (DOUBLE CHECKING PI(X) COMPUTATIONS) pi(x) / primecount . pi(x) --double-check . --double-check () . primecount : pi(x) ( ) . primecount 1e20 --status pi(x) () . primecount 1e20 --status --double-check pi(x) () . (EXAMPLES) primecount 1000 1000. primecount 1e17 --status 10^17 . primecount 1e15 --threads 1 --time 10^15 . (HOMEPAGE) https://github.com/kimwalisch/primecount (AUTHOR) Kim Walisch 04/16/2026 PRIMECOUNT(1)