/*
  https://medium.com/@themahfujur/17-can-you-solve-this-puzzle-many-people-fail-to-answer-this-viral-problem-78dfa1d017c6
  """
  9 = 72
  8 = 56
  7 = 42
  6 = 30
  5 = 20
  3 = ?
  """

  The "most probable" formula would be
    n * (n-1) = x
   9 * 8      = 72
   8 * 7      = 56
   7 * 6      = 42
   ...
  
  So 3 should be 3*2 = 6.
  
  Solutions:
  [program = (A - A / A) * A,res = 6.0,count = 16]
  [program = A * (A - 1),res = 6,count = 12]
  [program = A + (A - A * (2 * 2 - A)) + A,res = 6,count = 8]
  [program = (A - 1) * A,res = 6,count = 8]
  [program = A * A - A,res = 6,count = 7]
  [program = A + (A + (A - A * (2 * 2 - A))),res = 6,count = 6]
  [program = A * (A - A / A),res = 6.0,count = 5]
  [program = A * A - A + 0 * 0,res = 6,count = 3]
  [program = 0 * (A / 8) + (A * A - A),res = 6.0,count = 3]
  [program = A * A - 1 * A,res = 6,count = 1]

  resultMap = [6 = 7,6.0 = 3]

  It _could_ also be interpreted as
   x* (x - the number above - 2):
  3 * (5-2) = 3*3 = 9
  See equation3b for this and other solutions.


  Cf http://hakank.org/jgap/equation3.conf

*/
data(equation3,Data,Vars,Unknown,Ops,Constants,MaxSize,Params) :-
  Data = [ [[9],72],
           [[8],56],
           [[7],42],
           [[6],30],
           [[5],20]
          ],
  Ops = [+,-,*,/],
  Constants = 0..10,
  Vars = ['A'],
  Unknown = [3],
  Params = new_map([num_gens=20]),
  MaxSize = 21.