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project structure
Solution #1: Multiples of 3 and 5
Solution #2: Even Fibonacci numbers
Solution #3: Largest prime factor
Solution #4: Largest palindrome product
Solution #5: Smallest multiple
Solution #6: Sum square difference
Solution #7: 10001st prime
Solution #8: Largest product in a series
Solution #9: Special Pythagorean triplet
Solution #10: Summation of primes
Solution #11: Largest product in a grid
Solution #13: Large sum
Solution #14: Longest Collatz sequence
Solution #15: Lattice paths
Solution #16: Power digit sum
Solution #17: Number letter counts
Solution #18: Maximum path sum I