text: from oeis import A000217
  
  
  def test_sequence():
      assert A000217[:20] == [
          0,
          1,
          3,
          6,
          10,
          15,
          21,
          28,
          36,
          45,
          55,
          66,
          78,
          91,
          105,
          120,
          136,
          153,
          171,
          190,
      ]
  