gf24238

UID: 325, 注册于 2024-8-5 22:12:52, 最后登录于 2025-9-14 11:00:06, 目前离线.

解决了 473 道题目，RP: 258.33 (No. 12)

个人简介

$\Huge \varphi(x) = x \prod_{p | x} \left(1 - \frac{1}{p}\right)$

$\huge \sum^{i = 1}_{n} i^2 = \frac{n\times(n+1)\times(2n+1)}{6}$
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