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发表于 2026-9-12 19:18
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本帖最后由 cuikun-186 于 2026-9-14 19:56 编辑
# \(N=160000,\ r_2(N)=1196\times2=2392\)
\(\boldsymbol{\pi(160000)=14893}\)(不大于 160000 素数个数)
① 崔坤恒等式:\(C(N)=r_2(N)-2\pi(N)+\dfrac N2\)
\(\begin{align*}
C(160000)&=2392 - 2\times14893 + \frac{160000}{2}\\
&=2392 - 29786 + 80000\\
&=\boldsymbol{52606}
\end{align*}\)
② \(r_2(N)\ge \dfrac{\pi(N)^2}{N}\)
\(\frac{\pi(N)^2}{N}=\frac{14893^2}{160000}=\frac{221801449}{160000}\approx1386.26\)
\(2392 \ge 1386.26 \quad \boldsymbol{\checkmark}\)
③ 崔坤-切比雪夫下界 \(r_2(N)\ge \dfrac{0.8488\,N}{(\ln N)^2}\)
\(\ln 160000\approx 11.9829,\quad (\ln160000)^2\approx143.59\)
\(\frac{0.8488\times 160000}{(\ln 160000)^2}\approx \frac{135808}{143.59}\approx 945.80\)
\(2392 \ge 945.80 \quad \boldsymbol{\checkmark}\)
④ 崔坤-罗瑟合数对下界:
\(C(N)\ge \frac N2+\frac{0.8488N}{(\ln N)^2}-\frac{2.51012N}{\ln N}\)
\(\frac{2.51012\times 160000}{11.9829}\approx 33501.18\)
\(\text{右边}=80000+945.80-33501.18=\boldsymbol{47444.62}\)
\(C(160000)=52606 \ge 47444.62 \quad \boldsymbol{\checkmark}\) |
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