![Square Pyramidal Number Evolution [ 55 → 91 ]](https://cdn2.scratch.mit.edu/get_image/project/459450674_480x360.png)
Another based on the tetrahedral numbers, this one's the square pyramid number sequence. Tetrahedral numbers are triangular pyramid numbers, which are the result of consecutively adding triangular numbers. However, square pyramid numbers are the result of consecutively adding square numbers. So, therefore, Any n-gonal pyramid number is the sum of n-gonal numbers. The formula for square pyramid numbers is n(n+1)(2n+1)/6.
C2A!
