November 2018 Fiendish Function

The Fiendish Function posed during November 2018 had the following sample guesses and replies:

  • GUESS
  • REPLY
  • 1
  • 2
  • 2
  • 3
  • 3
  • 4
  • 4
  • 4
  • 5
  • 5
  • 10
  • 6

The rule was: "Write the number in binary, then add 2 to the power of the digits together".

Suppose the guess was 22:

  • Write the number in binary, giving 10110.
  • Take the number's digits, giving 1, 0, 1, 1, 0
  • Take 2 to the power of each digit, giving 2, 1, 2, 2, 1
  • Add these together, giving 8.

So the result is 8.