Logic Building
def sum_odd(n):
# Base case
if n == 0:
return 0
# Recursive case
# nth odd number is 2*n - 1
return (2 * n - 1) + sum_odd(n - 1)
# Test
n = int(input("Enter n: "))
result = sum_odd(n)
print(f"Sum of first {n} odd numbers: {result}")Output
Enter n: 5 Sum of first 5 odd numbers: 25
Nth odd number is 2*n - 1.
Key Concepts:
- Base case: sum(0) = 0
- Nth odd number = 2*n - 1
- Add current odd number to sum of previous