// project euler stats

// solved problems

Chronological list of all problems solved.

• Two-Dimensional Recurrence

  Problem 940 · Solved 20 Apr 25 (00:28)

• Exhausting a Colour

  Problem 938 · Solved 30 Mar 25 (14:29)

• 2025

  Problem 932 · Solved 15 Feb 25 (19:17)

• Recursive Sequence Summation

  Problem 918 · Solved 25 Nov 24 (20:03)

• Counting Fractions

  Problem 72 · Solved 09 Jul 24 (02:49)

• Monopoly Odds

  Problem 84 · Solved 09 Jul 24 (02:02)

• Cuboid Route

  Problem 86 · Solved 07 Jul 24 (23:07)

• Pythagorean Tree

  Problem 395 · Solved 07 Jul 24 (01:49)

• N^th Digit of Reciprocals

  Problem 820 · Solved 03 Jul 24 (15:18)

• Maximal n-gon in a region

  Problem 897 · Solved 01 Jul 24 (14:35)

• Eulercoin

  Problem 700 · Solved 26 Jun 24 (15:15)

• Number Splitting

  Problem 719 · Solved 25 Jun 24 (22:32)

• A Bold Proposition

  Problem 836 · Solved 21 Jun 24 (02:46)

• Laser Beam Reflections

  Problem 144 · Solved 21 Jun 24 (02:19)

• Poker Hands

  Problem 54 · Solved 18 Jun 24 (09:06)

• Spiral of Circles

  Problem 894 · Solved 17 Jun 24 (03:12)

• Shortest Distance Among Points

  Problem 816 · Solved 31 Jan 23 (22:08)

• Reversible Prime Squares

  Problem 808 · Solved 18 Sep 22 (12:22)

• Hybrid Integers

  Problem 800 · Solved 30 May 22 (07:10)

• Sliding Block Puzzle

  Problem 766 · Solved 03 Oct 21 (19:57)

• Pandigital Fibonacci Ends

  Problem 104 · Solved 19 Sep 21 (00:05)

• Triangle Containment

  Problem 102 · Solved 18 Sep 21 (23:46)

• Hollow Square Laminae I

  Problem 173 · Solved 13 Jun 21 (19:49)

• Roman Numerals

  Problem 89 · Solved 14 Mar 21 (17:19)

• Concatenation Coincidence

  Problem 751 · Solved 14 Mar 21 (01:37)

• Coin Loops

  Problem 737 · Solved 11 Dec 20 (20:09)

• Triangle of Circular Arcs

  Problem 727 · Solved 27 Sep 20 (01:55)

• Powers of Two

  Problem 686 · Solved 26 Oct 19 (21:05)

• Largest Roots of Cubic Polynomials

  Problem 356 · Solved 05 Apr 19 (15:30)

• Sums of Subarrays

  Problem 663 · Solved 31 Mar 19 (22:22)

• Fibonacci Paths

  Problem 662 · Solved 24 Mar 19 (21:04)

• Iterative Circle Packing

  Problem 199 · Solved 23 Mar 19 (15:08)

• Tours on a 4 × N Playing Board

  Problem 237 · Solved 20 Mar 19 (22:35)

• Chocolate Covered Candy

  Problem 449 · Solved 20 Mar 19 (11:03)

• Polynomials of Fibonacci Numbers

  Problem 435 · Solved 19 Mar 19 (21:03)

• Marsh Crossing

  Problem 607 · Solved 11 Mar 19 (18:39)

• Enmeshed Unit Circle

  Problem 392 · Solved 11 Mar 19 (14:16)

• Pandigital Triangles

  Problem 660 · Solved 10 Mar 19 (16:34)

• Magic 5-gon Ring

  Problem 68 · Solved 08 Mar 19 (19:03)

• Coin Partitions

  Problem 78 · Solved 08 Mar 19 (17:17)

• Pythagorean Ant

  Problem 613 · Solved 06 Mar 19 (17:46)

• Bézier Curves

  Problem 363 · Solved 06 Mar 19 (14:32)

• The Primality of 2n^2 - 1

  Problem 216 · Solved 05 Mar 19 (20:06)

• Tribonacci Non-divisors

  Problem 225 · Solved 04 Mar 19 (23:01)

• Largest Prime

  Problem 659 · Solved 02 Mar 19 (18:48)

• Incomplete Words

  Problem 657 · Solved 23 Feb 19 (19:39)

• Firecracker

  Problem 317 · Solved 18 Feb 19 (21:00)

• Palindromic Sequences

  Problem 656 · Solved 17 Feb 19 (12:55)

• Hilbert's New Hotel

  Problem 359 · Solved 15 Feb 19 (14:28)

• Efficient Exponentiation

  Problem 122 · Solved 13 Feb 19 (22:49)

• Prime Square Remainders

  Problem 123 · Solved 13 Feb 19 (20:22)

• A Lagged Fibonacci Sequence

  Problem 258 · Solved 07 Feb 19 (20:41)

• Linear Transformations of Polygonal Numbers

  Problem 647 · Solved 05 Feb 19 (20:09)

• Neighbourly Constraints

  Problem 654 · Solved 04 Feb 19 (17:15)

• Arranged Probability

  Problem 100 · Solved 02 Feb 19 (23:25)

• Hexagonal Tile Differences

  Problem 128 · Solved 02 Feb 19 (21:32)

• Square Remainders

  Problem 120 · Solved 31 Jan 19 (20:47)

• Optimum Polynomial

  Problem 101 · Solved 30 Jan 19 (23:44)

• Prime Summations

  Problem 77 · Solved 30 Jan 19 (14:58)

• Integer Partition Equations

  Problem 207 · Solved 30 Jan 19 (14:41)

• Bitwise-OR Operations on Random Integers

  Problem 323 · Solved 29 Jan 19 (19:23)

• Divisors of Binomial Product

  Problem 650 · Solved 23 Jan 19 (22:52)

• (prime-k) Factorial

  Problem 381 · Solved 18 Nov 18 (15:53)

• Diophantine Reciprocals I

  Problem 108 · Solved 13 Oct 18 (18:59)

• Right Triangles with Integer Coordinates

  Problem 91 · Solved 15 Aug 18 (00:32)

• Concave Triangle

  Problem 587 · Solved 23 May 18 (22:01)

• Rolling Ellipse

  Problem 525 · Solved 18 May 18 (19:57)

• Semiprimes

  Problem 187 · Solved 27 Feb 18 (17:06)

• Prime Generating Integers

  Problem 357 · Solved 26 Feb 18 (14:43)

• Bouncy Numbers

  Problem 112 · Solved 26 Feb 18 (13:13)

• Palindromic Sums

  Problem 125 · Solved 25 Feb 18 (15:40)

• Digit Factorial Chains

  Problem 74 · Solved 24 Feb 18 (20:51)

• Counting Fractions in a Range

  Problem 73 · Solved 24 Feb 18 (20:21)

• Su Doku

  Problem 96 · Solved 22 Feb 18 (18:59)

• XOR Decryption

  Problem 59 · Solved 20 Feb 18 (17:11)

• Counting Summations

  Problem 76 · Solved 10 Feb 18 (20:13)

• Path Sum: Two Ways

  Problem 81 · Solved 10 Feb 18 (19:28)

• Passcode Derivation

  Problem 79 · Solved 10 Feb 18 (17:12)

• Prime Power Triples

  Problem 87 · Solved 10 Feb 18 (15:59)

• π Sequences

  Problem 609 · Solved 05 Feb 18 (19:54)

• Hollow Square Laminae II

  Problem 174 · Solved 05 Aug 17 (02:15)

• Counting Rectangles

  Problem 85 · Solved 05 Aug 17 (01:24)

• Prime Permutations

  Problem 49 · Solved 19 Jan 17 (20:29)

• Consecutive Positive Divisors

  Problem 179 · Solved 22 Sep 16 (22:13)

• Ordered Radicals

  Problem 124 · Solved 22 Sep 16 (20:35)

• Reversible Numbers

  Problem 145 · Solved 22 Sep 16 (18:46)

• Concealed Square

  Problem 206 · Solved 21 Sep 16 (14:21)

• Large Non-Mersenne Prime

  Problem 97 · Solved 20 Sep 16 (19:25)

• Largest Exponential

  Problem 99 · Solved 20 Sep 16 (18:59)

• Square Digit Chains

  Problem 92 · Solved 20 Sep 16 (18:09)

• Square Root Digital Expansion

  Problem 80 · Solved 19 Sep 16 (17:07)

• Ordered Fractions

  Problem 71 · Solved 18 Sep 16 (22:45)

• Totient Permutation

  Problem 70 · Solved 18 Sep 16 (20:32)

• Totient Maximum

  Problem 69 · Solved 18 Sep 16 (19:02)

• Diophantine Equation

  Problem 66 · Solved 18 Sep 16 (04:35)

• Convergents of e

  Problem 65 · Solved 18 Sep 16 (02:36)

• Odd Period Square Roots

  Problem 64 · Solved 18 Sep 16 (00:47)

• Powerful Digit Counts

  Problem 63 · Solved 17 Sep 16 (14:30)

• Cubic Permutations

  Problem 62 · Solved 17 Sep 16 (13:26)

• Cyclical Figurate Numbers

  Problem 61 · Solved 17 Sep 16 (12:53)

• Prime Pair Sets

  Problem 60 · Solved 17 Sep 16 (02:26)

• Spiral Primes

  Problem 58 · Solved 16 Sep 16 (23:51)

• Square Root Convergents

  Problem 57 · Solved 16 Sep 16 (23:05)

• Powerful Digit Sum

  Problem 56 · Solved 16 Sep 16 (21:30)

• Lychrel Numbers

  Problem 55 · Solved 16 Sep 16 (21:07)

• Combinatoric Selections

  Problem 53 · Solved 16 Sep 16 (18:42)

• Permuted Multiples

  Problem 52 · Solved 16 Sep 16 (18:07)

• Prime Digit Replacements

  Problem 51 · Solved 16 Sep 16 (17:34)

• Sub-string Divisibility

  Problem 43 · Solved 16 Sep 16 (15:20)

• Lexicographic Permutations

  Problem 24 · Solved 16 Sep 16 (01:50)

• Non-Abundant Sums

  Problem 23 · Solved 16 Sep 16 (00:51)

• Consecutive Prime Sum

  Problem 50 · Solved 15 Sep 16 (23:46)

• Self Powers

  Problem 48 · Solved 15 Sep 16 (22:22)

• Distinct Primes Factors

  Problem 47 · Solved 15 Sep 16 (22:13)

• Goldbach's Other Conjecture

  Problem 46 · Solved 15 Sep 16 (21:28)

• Triangular, Pentagonal, and Hexagonal

  Problem 45 · Solved 15 Sep 16 (20:52)

• Pentagon Numbers

  Problem 44 · Solved 15 Sep 16 (20:20)

• Coded Triangle Numbers

  Problem 42 · Solved 15 Sep 16 (19:20)

• Pandigital Prime

  Problem 41 · Solved 15 Sep 16 (19:03)

• Champernowne's Constant

  Problem 40 · Solved 15 Sep 16 (17:54)

• Integer Right Triangles

  Problem 39 · Solved 15 Sep 16 (17:39)

• Pandigital Multiples

  Problem 38 · Solved 15 Sep 16 (16:54)

• Truncatable Primes

  Problem 37 · Solved 15 Sep 16 (15:56)

• Double-base Palindromes

  Problem 36 · Solved 15 Sep 16 (15:27)

• Circular Primes

  Problem 35 · Solved 15 Sep 16 (03:29)

• Digit Factorials

  Problem 34 · Solved 15 Sep 16 (02:06)

• Digit Cancelling Fractions

  Problem 33 · Solved 15 Sep 16 (01:51)

• Reciprocal Cycles

  Problem 26 · Solved 15 Sep 16 (01:10)

• Pandigital Products

  Problem 32 · Solved 14 Sep 16 (19:56)

• Coin Sums

  Problem 31 · Solved 14 Sep 16 (19:06)

• Digit Fifth Powers

  Problem 30 · Solved 14 Sep 16 (18:01)

• Counting Sundays

  Problem 19 · Solved 14 Sep 16 (17:40)

• Distinct Powers

  Problem 29 · Solved 14 Sep 16 (15:58)

• Number Spiral Diagonals

  Problem 28 · Solved 14 Sep 16 (04:43)

• Quadratic Primes

  Problem 27 · Solved 14 Sep 16 (03:43)

• 1000-digit Fibonacci Number

  Problem 25 · Solved 13 Sep 16 (21:02)

• Names Scores

  Problem 22 · Solved 13 Sep 16 (20:07)

• Amicable Numbers

  Problem 21 · Solved 13 Sep 16 (19:17)

• Factorial Digit Sum

  Problem 20 · Solved 13 Sep 16 (18:40)

• Maximum Path Sum II

  Problem 67 · Solved 13 Sep 16 (18:14)

• Maximum Path Sum I

  Problem 18 · Solved 13 Sep 16 (17:01)

• Number Letter Counts

  Problem 17 · Solved 13 Sep 16 (15:59)

• Power Digit Sum

  Problem 16 · Solved 13 Sep 16 (15:23)

• Lattice Paths

  Problem 15 · Solved 13 Sep 16 (15:09)

• Longest Collatz Sequence

  Problem 14 · Solved 13 Sep 16 (13:50)

• Large Sum

  Problem 13 · Solved 13 Sep 16 (13:34)

• Highly Divisible Triangular Number

  Problem 12 · Solved 12 Sep 16 (23:45)

• Largest Product in a Grid

  Problem 11 · Solved 12 Sep 16 (21:53)

• Largest Product in a Series

  Problem 8 · Solved 12 Sep 16 (21:26)

• Largest Palindrome Product

  Problem 4 · Solved 12 Sep 16 (21:12)

• Multiples of 3 or 5

  Problem 1 · Solved 12 Sep 16 (20:55)

• Even Fibonacci Numbers

  Problem 2 · Solved 12 Sep 16 (20:44)

• 10 001st Prime

  Problem 7 · Solved 02 Apr 16 (14:57)

• Sum Square Difference

  Problem 6 · Solved 02 Apr 16 (14:43)

• Summation of Primes

  Problem 10 · Solved 30 Mar 16 (22:09)

• Special Pythagorean Triplet

  Problem 9 · Solved 30 Mar 16 (22:03)

• Smallest Multiple

  Problem 5 · Solved 30 Mar 16 (20:57)

• Largest Prime Factor

  Problem 3 · Solved 30 Mar 16 (20:48)