def human_years_cat_years_dog_years(human_years):

    if human_years == 1:
        return human_years, 15 / human_years, 15 / human_years
    elif human_years == 2:
        return human_years, 15 * human_years - 15 + 9, 15 * human_years - 15 + 9
    elif human_years >= 3:
        humanYears = human_years
        catYears = (human_years - 2) * 4 + 15 * 2 - 15 + 9
        dogYears = (human_years - 2) * 5 + 15 * 2 - 15 + 9
        return [humanYears, catYears, dogYears]

print(human_years_cat_years_dog_years(10))