April 2015 Fiendish Function

The Fiendish Function posed during April 2015 had the following sample guesses and replies:

• GUESS
• REPLY
• 1
• 1
• 2
• 16
• 3
• 81
• 4
• 37
• 5
• 29
• 10
• 1

The rule was: "Square the number, then add the squares of the digits together".

Suppose the guess was 12:

• Square the number, giving 144.
• Take the number's digits, giving 1, 4, 4
• Square them, giving 1, 16, 16
• Add these together, giving 33.

So the result is 33.