My solutions to the problems of the Project Euler
| № | Title | Solution |
|---|---|---|
| 1 | Multiples of 3 and 5 | 233168 |
| 2 | Even Fibonacci numbers | 4613732 |
| 3 | Largest prime factor | 6857 |
| 4 | Largest palindrome product | 906609 |
| 5 | Smallest multiple | 232792560 |
| 6 | Sum square difference | 25164150 |
| 7 | 10001st prime | 104743 |
| 8 | Largest product in a series | 23514624000 |
| 9 | Special Pythagorean triplet | 31875000 |
| 10 | Summation of primes | 142913828922 |
| 11 | Largest product in a grid | 70600674 |
| 12 | Highly divisible triangular number | 76576500 |
| 13 | Large sum | 5537376230 |
| 14 | Longest Collatz sequence | 837799 |
| 15 | Lattice paths | 137846528820 |
| 16 | Power digit sum | 1366 |
| 17 | Number letter counts | 21124 |
| 18 | Maximum path sum I | 1074 |
| 19 | Counting Sundays | 171 |
| 20 | Factorial digit sum | 648 |
| 21 | Amicable numbers | 31626 |
| 22 | Names scores | 871198282 |
| 23 | Non-abundant sums | 4179871 |
| 24 | Lexicographic permutations | 2783915460 |
| 25 | 1000-digit Fibonacci number | 4782 |
| 26 | Reciprocal cycles | 983 |
| 27 | Quadratic primes | -59231 |
| 28 | Number spiral diagonals | 669171001 |
| 29 | Distinct powers | 9183 |
| 30 | Digit fifth powers | 443839 |
| 31 | Coin sums | 73682 |
| 32 | Pandigital products | 45228 |
| 33 | Digit cancelling fractions | 100 |
| 34 | Digit factorials | 40730 |
| 35 | Circular primes | 55 |
| 36 | Double-base palindromes | 872187 |
| 37 | Truncatable primes | 748317 |
| 38 | Pandigital multiples | 932718654 |
| 39 | Integer right triangles | 840 |
| 40 | Champernowne's constant | 210 |
| 41 | Pandigital prime | 7652413 |
| 42 | Coded triangle numbers | 748317 |
| 43 | Sub-string divisibility | 16695334890 |
| 44 | Pentagon numbers | 5482660 |
| 45 | Triangular, pentagonal, and hexagonal | 1533776805 |
| 46 | Goldbach's other conjecture | 5777 |
| 47 | Distinct primes factors | 134043 |
| 48 | Self powers | 9110846700 |
| 49 | Prime permutations | 296962999629 |
| 50 | Consecutive prime sum | 997651 |
| 51 | Prime digit replacements | 121313 |
| 52 | Permuted multiples | 142857 |
| 53 | Combinatoric selections | 4075 |
| 54 | Poker hands | 376 |
| 55 | Lychrel numbers | 249 |
| 56 | Powerful digit sum | 972 |
| 57 | Square root convergents | 153 |
| 58 | Spiral primes | 26241 |
| 59 | XOR decryption | 107359 |
| 60 | Prime pair sets | 26033 |
| 61 | Cyclical figurate numbers | 28684 |
| 62 | Cubic permutations | 127035954683 |
| 63 | Powerful digit counts | 49 |
| 64 | Odd period square roots | 1322 |
| 65 | Convergents of e | 272 |