user070223

  from pysr import PySRRegressor

  def f(n):
      if n % 15 == 0:
          return 3
      elif n%5 == 0:
          return 2
      elif n%3 == 0:
          return 1
      return 0

  n = 500
  X = np.array(range(1,n)).reshape(-1,1)
  Y = np.array([f(n) for n in range(1,n)]).reshape(-1,1)
  model = PySRRegressor(
          maxsize=25,
          niterations=200,  # < Increase me for better results
          binary_operators=["+", "*"],
          unary_operators=["cos", "sin", "exp"],
          elementwise_loss="loss(prediction, target) = (prediction - target)^2",

  model.fit(X,Y)