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Problems Archives

The problems archives table shows problems 1 to 652. 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
1116
252Convex Holes
680
253Tidying up
841
254Sums of Digit Factorials
782
255Rounded Square Roots
722
256Tatami-Free Rooms
594
257Angular Bisectors
542
258A lagged Fibonacci sequence
1287
259Reachable Numbers
1275
260Stone Game
1082
261Pivotal Square Sums
547
262Mountain Range
581
263An engineers' dream come true
854
264Triangle Centres
464
265Binary Circles
3607
266Pseudo Square Root
1415
267Billionaire
2832
268Counting numbers with at least four distinct prime factors less than 100
1181
269Polynomials with at least one integer root
555
270Cutting Squares
526
271Modular Cubes, part 1
1959
272Modular Cubes, part 2
758
273Sum of Squares
1115
274Divisibility Multipliers
1198
275Balanced Sculptures
500
276Primitive Triangles
878
277A Modified Collatz sequence
2697
278Linear Combinations of Semiprimes
837
279Triangles with integral sides and an integral angle
567
280Ant and seeds
851
281Pizza Toppings
763
282The Ackermann function
796
283Integer sided triangles for which the area/perimeter ratio is integral
538
284Steady Squares
1042
285Pythagorean odds
970
286Scoring probabilities
1765
287Quadtree encoding (a simple compression algorithm)
1184
288An enormous factorial
1352
289Eulerian Cycles
390
290Digital Signature
812
291Panaitopol Primes
1153
292Pythagorean Polygons
477
293Pseudo-Fortunate Numbers
2428
294Sum of digits - experience #23
749
295Lenticular holes
383
296Angular Bisector and Tangent
478
297Zeckendorf Representation
2362
298Selective Amnesia
555
299Three similar triangles
511
300Protein folding
892