关于一个组合恒等式

学术版

Diaоsi @ 2024-09-18 21:37:28

注意到

\dbinom{n}{2k}2^{2k}=\sum\limits_{i=0}^k(-1)^i\dbinom{n}{i}\dbinom{2n-2i}{2k-2i}

这个式子从组合意义上来看是正确的，想寻求一些代数推导方式。

目前的思路是用 \mathbf{GF} 硬做，想知道有没有更优美的做法。

by 小粉兔 @ 2024-09-19 21:18:11

代数推导天地灭，组合意义保平安。

by Diaоsi @ 2024-09-20 00:00:15

@小粉兔 已经天地灭了/fn/fn

by Diaоsi @ 2024-09-20 00:01:17

@小粉兔 主播有没有什么高论/kel

by HydrogenOxygen @ 2025-10-23 09:08:07

qp+两个管理楼下

by qmSHUANG99 @ 2025-10-23 10:39:12

qp

by gaohongyuan @ 2025-10-23 12:22:59

qp

by zjck2 @ 2025-10-23 12:24:52

qp，第一次这么前

by qu_ming_zhen_nan @ 2025-10-23 19:55:06

qp(?

by Super_Aierdeng @ 2025-10-24 20:46:32

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