From 0e715c9c810c47f3b4a7b5dacdbe428d7f9b1b6c Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Mon, 16 Feb 2026 23:43:48 +0900
Subject: [PATCH] baekjoon 20260216

---
 code_study/Baekjoon/python/2921.py | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 code_study/Baekjoon/python/2921.py

diff --git a/code_study/Baekjoon/python/2921.py b/code_study/Baekjoon/python/2921.py
new file mode 100644
index 0000000..a83238a
--- /dev/null
+++ b/code_study/Baekjoon/python/2921.py
@@ -0,0 +1,10 @@
+N = int(input())
+
+sigma = lambda k : int(0.5*k*(k+1))
+
+ans = 0
+for n in range(1,N+1) :
+    if n==1 : ans = 3
+    else : ans += sigma(n) + n*(n+1)
+
+print(ans)
\ No newline at end of file