Program in bash, linux:

The difference of the square of the sum of the first 7 numbers and the sum of the squares of the first 7 numbers is:

(1 + 2 + ... + 7) ^ 2 - (1 ^ 2 + 2 ^ 2 + ... + 7 ^ 2) = 644

The program must:

1.Calculate the difference of the square of a number, entering by the user

2.In the result shown, you must express the mathematical notation, that is:

(1 + 2 + ... + 7) ^ 2 - (1 ^ 2 + 2 ^ 2 + ... + 7 ^ 2) = 644