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Problems Archives

The problems archives table shows problems 1 to 667. 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
1140
252Convex Holes
702
253Tidying up
869
254Sums of Digit Factorials
799
255Rounded Square Roots
735
256Tatami-Free Rooms
613
257Angular Bisectors
561
258A lagged Fibonacci sequence
1318
259Reachable Numbers
1303
260Stone Game
1106
261Pivotal Square Sums
561
262Mountain Range
598
263An engineers' dream come true
869
264Triangle Centres
473
265Binary Circles
3682
266Pseudo Square Root
1443
267Billionaire
2900
268Counting numbers with at least four distinct prime factors less than 100
1205
269Polynomials with at least one integer root
570
270Cutting Squares
537
271Modular Cubes, part 1
2005
272Modular Cubes, part 2
775
273Sum of Squares
1136
274Divisibility Multipliers
1226
275Balanced Sculptures
507
276Primitive Triangles
905
277A Modified Collatz sequence
2739
278Linear Combinations of Semiprimes
857
279Triangles with integral sides and an integral angle
582
280Ant and seeds
876
281Pizza Toppings
785
282The Ackermann function
822
283Integer sided triangles for which the area/perimeter ratio is integral
549
284Steady Squares
1063
285Pythagorean odds
1004
286Scoring probabilities
1804
287Quadtree encoding (a simple compression algorithm)
1213
288An enormous factorial
1391
289Eulerian Cycles
403
290Digital Signature
833
291Panaitopol Primes
1189
292Pythagorean Polygons
488
293Pseudo-Fortunate Numbers
2504
294Sum of digits - experience #23
767
295Lenticular holes
391
296Angular Bisector and Tangent
489
297Zeckendorf Representation
2400
298Selective Amnesia
573
299Three similar triangles
521
300Protein folding
918