First, let’s take a look at what this problem entails: “Find the sum of digits which can be formed from the numbers in the Fibonacci sequence to a given nth number.” Sounds easy enough, right? Well, not exactly. The catch is that we have to find all possible combinations of digits and add them up.

Now, if you’re like me and don’t want to spend hours upon hours manually calculating each combination, there’s a much easier way using Python! Here’s the code:

# Define a function to calculate the sum of digits in a Fibonacci sequence up to the nth number
def sum_digits(n):
    # Initialize variables for the first two numbers in the Fibonacci sequence
    fib1 = 0 # First number in the sequence
    fib2 = 1 # Second number in the sequence
    
    # Check if n is less than or equal to 1 (base case)
    if n <= 1:
        return n # If n is 0 or 1, return n as the sum of digits is equal to n
        
    # Calculate sum of digits in Fibonacci sequence up to nth number
    for i in range(2, n+1): # Loop through numbers from 2 to n (inclusive)
        fib3 = fib1 + fib2 # Calculate the next number in the Fibonacci sequence
        # Check if any digit is greater than or equal to 9 (if so, add the corresponding single-digit numbers)
        while fib3 >= 10: # Loop until all digits in fib3 are less than 10
            sum_of_digits += fib3 % 10 + fib3 // 10 # Add the last digit of fib3 to the sum of digits and remove it from fib3
            fib3 = fib2 + fib3 // 10 # Update fib3 by removing the last digit
        # Add current digit to sum of digits
        sum_of_digits += fib3 # Add the remaining digit in fib3 to the sum of digits
        # Update variables for next Fibonacci number
        fib1, fib2 = fib2, fib3 # Update fib1 and fib2 to the next two numbers in the sequence
    
    return sum_of_digits # Return the final sum of digits in the Fibonacci sequence

Now let’s break this down:
– We first initialize two variables (fib1 and fib2) to hold the previous two numbers in the Fibonacci sequence.
– Next, we check if n is less than or equal to 1 this is our base case for when we only need to return the input number itself since it’s already a single digit.
– We then loop through each subsequent number in the Fibonacci sequence (starting from index 2) up until the nth number.
– For each new number, we calculate its value by adding the previous two numbers together and storing that result as fib3.
– If any of the digits in this new number are greater than or equal to 10, we add the corresponding single-digit numbers (i.e., if the first digit is a 9, we add both the 9 and the second digit together).
– We then add the current digit to our sum_of_digits variable.
– Finally, we update fib1 and fib2 for the next iteration of the loop.

And that’s it! With this code, you can easily solve Project Euler problem 034 in no time at all. So go ahead give it a try and let us know how it goes!