
    Design a function that calculates the total number of learning concepts a student has mastered after completing n levels in their personalized learning path, where each new level introduces more interconnected concepts than the previous one in a triangular layered pattern. The progression follows a pattern where each level builds upon previous levels by adding concepts that connect with multiple previously learned topics, forming a three-dimensional knowledge structure.
    

    
def tetrahedral_number(n):
    """
    Design a function that calculates the total number of learning concepts a student has mastered after completing n levels in their personalized learning path, where each new level introduces more interconnected concepts than the previous one in a triangular layered pattern. The progression follows a pattern where each level builds upon previous levels by adding concepts that connect with multiple previously learned topics, forming a three-dimensional knowledge structure.
    

    """
def tetrahedral_number(n):
    """
    Design a function that calculates the total number of learning concepts a student has mastered after completing n levels in their personalized learning path, where each new level introduces more interconnected concepts than the previous one in a triangular layered pattern. The progression follows a pattern where each level builds upon previous levels by adding concepts that connect with multiple previously learned topics, forming a three-dimensional knowledge structure.
    

    """
    return n * (n + 1) * (n + 2) / 6