Cache update: 50 minutes

Problems Archives

The problems archives table shows problems 1 to 682. If you would like to tackle the 10 most recently published problems then go to Recent problems.
Click the description/title of the problem to view details and submit your answer.


IDDescription / TitleSolved By
551Sum of digits sequence
384
552Chinese leftovers II
340
553Power sets of power sets
170
554Centaurs on a chess board
175
555McCarthy 91 function
565
556Squarefree Gaussian Integers
178
557Cutting triangles
239
558Irrational base
195
559Permuted Matrices
136
560Coprime Nim
232
561Divisor Pairs
610
562Maximal perimeter
153
563Robot Welders
261
564Maximal polygons
194
565Divisibility of sum of divisors
494
566Cake Icing Puzzle
115
567Reciprocal games I
216
568Reciprocal games II
210
569Prime Mountain Range
321
570Snowflakes
223
571Super Pandigital Numbers
858
572Idempotent matrices
269
573Unfair race
162
574Verifying Primes
215
575Wandering Robots
446
576Irrational jumps
185
577Counting hexagons
1254
578Integers with decreasing prime powers
177
579Lattice points in lattice cubes
112
580Squarefree Hilbert numbers
182
58147-smooth triangular numbers
669
582Nearly isosceles 120 degree triangles
248
583Heron Envelopes
302
584Birthday Problem Revisited
138
585Nested square roots
124
586Binary Quadratic Form
179
587Concave triangle
2431
588Quintinomial coefficients
347
589Poohsticks Marathon
147
590Sets with a given Least Common Multiple
202
591Best Approximations by Quadratic Integers
138
592Factorial trailing digits 2
228
593Fleeting Medians
413
594Rhombus Tilings
150
595Incremental Random Sort
498
596Number of lattice points in a hyperball
281
597Torpids
119
598Split Divisibilities
390
599Distinct Colourings of a Rubik's Cube
237
600Integer sided equiangular hexagons
477