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Problems Archives

The problems archives table shows problems 1 to 627. 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
1071
252Convex Holes
664
253Tidying up
813
254Sums of Digit Factorials
756
255Rounded Square Roots
706
256Tatami-Free Rooms
574
257Angular Bisectors
523
258A lagged Fibonacci sequence
1217
259Reachable Numbers
1250
260Stone Game
1044
261Pivotal Square Sums
525
262Mountain Range
566
263An engineers' dream come true
835
264Triangle Centres
456
265Binary Circles
3479
266Pseudo Square Root
1358
267Billionaire
2762
268Counting numbers with at least four distinct prime factors less than 100
1145
269Polynomials with at least one integer root
542
270Cutting Squares
514
271Modular Cubes, part 1
1895
272Modular Cubes, part 2
731
273Sum of Squares
1080
274Divisibility Multipliers
1161
275Balanced Sculptures
486
276Primitive Triangles
860
277A Modified Collatz sequence
2620
278Linear Combinations of Semiprimes
810
279Triangles with integral sides and an integral angle
553
280Ant and seeds
821
281Pizza Toppings
733
282The Ackermann function
772
283Integer sided triangles for which the area/perimeter ratio is integral
529
284Steady Squares
1015
285Pythagorean odds
941
286Scoring probabilities
1712
287Quadtree encoding (a simple compression algorithm)
1139
288An enormous factorial
1301
289Eulerian Cycles
382
290Digital Signature
788
291Panaitopol Primes
1117
292Pythagorean Polygons
466
293Pseudo-Fortunate Numbers
2349
294Sum of digits - experience #23
711
295Lenticular holes
372
296Angular Bisector and Tangent
460
297Zeckendorf Representation
2311
298Selective Amnesia
542
299Three similar triangles
493
300Protein folding
864