[
    {
        "min_participants": 1,
        "max_participants": 10,
        "double_prob": 0.3
    },
    {
        "min_participants": 2,
        "max_participants": 7,
        "double_prob": 0.4
    },
    {
        "min_participants": 3,
        "max_participants": 15,
        "double_prob": 0.2
    },
    {
        "min_participants": 5,
        "max_participants": 20,
        "double_prob": 0.25
    }
]