The Sieve of Eratosthenes - a Simulation    

(Eratosthenes of Cyrene ca. 276-194 BC)
Author: Jochen Ziegenbalg, Karlsruhe (Germany)   http://www.ziegenbalg.ph-karlsruhe.de   [ A general description of the sieve procedure]
 
       upper limit (set arbitrarily or default = 250):        number of columns (set arbitrarily or default = 18):