Logic Building/Phase 3 - Level 3: Pattern Recursion/Program

Number Patterns Recursively

Print number pattern using recursion.

Logic BuildingIntermediate

Logic Building

def print_numbers(n, current=1):
    # Base case
    if current > n:
        return
    
    # Print current number
    print(current, end="")
    # Recurse
    print_numbers(n, current + 1)

def print_pattern(n, row=1):
    # Base case
    if row > n:
        return
    
    # Print row
    print_numbers(row)
    print()
    # Recurse
    print_pattern(n, row + 1)

# Test
n = int(input("Enter rows: "))
print_pattern(n)

Output

Enter rows: 4
1
12
123
1234

Use helper to print numbers, main function for rows.

Key Concepts:

Helper prints 1 to n
Main function prints rows
Recursive structure

Print Triangle (Bottom-Up) Recursively

Print Reverse Triangle Recursively