
    Design an algorithm for an adaptive learning platform that calculates the difficulty threshold at any given progression level n, where the threshold follows a pattern where each new value is determined by counting how many times the previous threshold appeared in earlier levels, starting with initial values of 1,1. The calculated threshold value helps determine when to adjust the complexity of learning materials for students.
    

    
def sequence(n):
    """
    Design an algorithm for an adaptive learning platform that calculates the difficulty threshold at any given progression level n, where the threshold follows a pattern where each new value is determined by counting how many times the previous threshold appeared in earlier levels, starting with initial values of 1,1. The calculated threshold value helps determine when to adjust the complexity of learning materials for students.
    

    """
def sequence(n):
    """
    Design an algorithm for an adaptive learning platform that calculates the difficulty threshold at any given progression level n, where the threshold follows a pattern where each new value is determined by counting how many times the previous threshold appeared in earlier levels, starting with initial values of 1,1. The calculated threshold value helps determine when to adjust the complexity of learning materials for students.
    

    """
    if n == 1 or n == 2:
        return 1
    else:
        return sequence(sequence(n - 1)) + sequence(n - sequence(n - 1))