1+2+3+4+5+6+7+...+n
=
三角形數
1+3+6+10+15+...+n
=
謝謝大家:).
更新1:
求公式:). 謝
更新2:
Seems like both of you made some mistakes@@?
求公式:). 謝
Seems like both of you made some mistakes@@?
收錄日期: 2021-04-21 00:14:09
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081108000051KK00673