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楼主 |
发表于 2020-12-3 22:17
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300以内的质数个数计算方法,
300/2-(49+19+10+5+4+1)=62,
300/2=150,为了计算简捷,我们直接将奇数1改成质数2,
(150-2)/3=49,
(150-8)/5=28, {(28-1)×2+5+1}/2=30,(30-2)/3=9, 28-9=19,
(150-18)/7=18, {(18-1)×2+7+1}/2-21, (21-2)/3=6, (21-8)/5=2, 18-6-2=10,
(150-50)/11=9, {(9-1)×2+11+1}/2=14,(14-2)/3=4, {(11+1)/2}-2/3=1, (14-8)/5=1, 9-(4-1)-1=5,
(150-72)/13=6, {(6-1)×2+13+1}/2=12, (12-2)/3=3, {(13+1)/2)-2}/3=1, 6-(3-1)=4,
(150-128)/17=1, |
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