Looking for a rule, there is a pile of exactly the same cubes. Counting from top to bottom, the first layer is 1, the second layer is 3, and the third layer is 10 , In the corner there was a pile of identical cube blocks Counting from top to bottom, the first layer is 1, the second layer is 3, and the third layer is 10 When it's five stories, it's a total of 35 blocks Are there any rules?

Looking for a rule, there is a pile of exactly the same cubes. Counting from top to bottom, the first layer is 1, the second layer is 3, and the third layer is 10 , In the corner there was a pile of identical cube blocks Counting from top to bottom, the first layer is 1, the second layer is 3, and the third layer is 10 When it's five stories, it's a total of 35 blocks Are there any rules?

an=1+2+3+4+.+n=n(n+1)/2