添加 'D.cpp'

D.cpp

@@ -0,0 +1,10 @@
+#include <stdio.h>
+int main() {
+  int m, n;
+  scanf("%d", &m);
+  while (m--) {
+    scanf("%d", &n);
+    printf("%d\n", n * (n + 1) * (n + 2) / 6);
+  }
+  return 0;
+}