Below is a possible solution to the challenge – Challenge 7 – Formula for Sum of Square of the Digits in an Alphanumeric String
Enter the below formula as Array Formula i.e. not by pressing ENTER after entering your formula but by pressing CTRL+SHIFT+ENTER. If you are copying and pasting this formula, take F2 after pasting and CTRL+SHIFT+ENTER. This will put { } brackets around the formula which you can see in Formula Bar. If you edit again, you will have to do CTRL+SHIFT+ENTER again. Don't put { } manually.
=SUM(IFERROR(MID(A1,ROW(INDIRECT("1:"&LEN(A1))),1)^2,0))