{"raw_statement":[{"iden":"background","content":"对应的选择、判断题：<https://ti.luogu.com.cn/problemset/1189>"},{"iden":"statement","content":"金字塔由 $n$ 层石块垒成。从塔底向上，每层依次需要 $n \\times n, (n-1) \\times (n-1), \\cdots, 2 \\times 2, 1 \\times 1$ 块石块。请问搭建金字塔总共需要多少块石块？"},{"iden":"input","content":"一行，一个正整数 $n$，表示金字塔的层数。"},{"iden":"output","content":"一行，一个正整数，表示搭建金字塔所需的石块数量。"},{"iden":"note","content":"对于所有测试点，保证 $1 \\leq n \\leq 50$。"}],"translated_statement":null,"sample_group":[["2","5"],["5","55"]],"show_order":[],"formal_statement":null,"simple_statement":null,"has_page_source":false}