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Problems Archives

The problems archives table shows problems 1 to 641. 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
251Cardano Triplets
1096
252Convex Holes
672
253Tidying up
831
254Sums of Digit Factorials
773
255Rounded Square Roots
718
256Tatami-Free Rooms
590
257Angular Bisectors
538
258A lagged Fibonacci sequence
1261
259Reachable Numbers
1268
260Stone Game
1069
261Pivotal Square Sums
542
262Mountain Range
574
263An engineers' dream come true
846
264Triangle Centres
458
265Binary Circles
3560
266Pseudo Square Root
1393
267Billionaire
2809
268Counting numbers with at least four distinct prime factors less than 100
1176
269Polynomials with at least one integer root
550
270Cutting Squares
519
271Modular Cubes, part 1
1936
272Modular Cubes, part 2
750
273Sum of Squares
1105
274Divisibility Multipliers
1184
275Balanced Sculptures
497
276Primitive Triangles
868
277A Modified Collatz sequence
2659
278Linear Combinations of Semiprimes
825
279Triangles with integral sides and an integral angle
559
280Ant and seeds
835
281Pizza Toppings
751
282The Ackermann function
786
283Integer sided triangles for which the area/perimeter ratio is integral
536
284Steady Squares
1033
285Pythagorean odds
961
286Scoring probabilities
1744
287Quadtree encoding (a simple compression algorithm)
1166
288An enormous factorial
1337
289Eulerian Cycles
389
290Digital Signature
800
291Panaitopol Primes
1143
292Pythagorean Polygons
470
293Pseudo-Fortunate Numbers
2404
294Sum of digits - experience #23
731
295Lenticular holes
378
296Angular Bisector and Tangent
474
297Zeckendorf Representation
2347
298Selective Amnesia
551
299Three similar triangles
505
300Protein folding
881