1. Multiples of 3 and 5 2. Even Fibonacci numbers 3. Largest prime factor 4. Largest palindrome product 5. Smallest multiple 6. Sum square difference 7. 10001st prime 8. Largest product in a series 9. Special Pythagorean triplet 10. Summation of primes 11. Largest product in a grid 12. Highly divisible triangular number 13. Large sum 14. Longest Collatz sequence 15. Lattice paths 16. Power digit sum 17. Number letter counts 18. Maximum path sum I 19. Counting Sundays 20. Factorial digit sum 21. Amicable numbers 22. Names scores 23. Non-abundant sums 24. Lexicographic permutations 25. 1000-digit Fibonacci number 28. Number spiral diagonals 29. Distinct powers 30. Digit fifth powers 34. Digit factorials 48. Self powers 67. Maximum path sum II