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Problems Archives

The problems archives table shows problems 1 to 713. 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
1226
252Convex Holes
742
253Tidying up
922
254Sums of Digit Factorials
846
255Rounded Square Roots
770
256Tatami-Free Rooms
651
257Angular Bisectors
605
258A lagged Fibonacci sequence
1438
259Reachable Numbers
1360
260Stone Game
1170
261Pivotal Square Sums
599
262Mountain Range
631
263An engineers' dream come true
916
264Triangle Centres
504
265Binary Circles
3877
266Pseudo Square Root
1521
267Billionaire
3096
268Counting numbers with at least four distinct prime factors less than 100
1291
269Polynomials with at least one integer root
608
270Cutting Squares
567
271Modular Cubes, part 1
2149
272Modular Cubes, part 2
842
273Sum of Squares
1230
274Divisibility Multipliers
1279
275Balanced Sculptures
537
276Primitive Triangles
961
277A Modified Collatz sequence
2944
278Linear Combinations of Semiprimes
923
279Triangles with integral sides and an integral angle
624
280Ant and seeds
923
281Pizza Toppings
845
282The Ackermann function
888
283Integer sided triangles for which the area/perimeter ratio is integral
576
284Steady Squares
1135
285Pythagorean odds
1076
286Scoring probabilities
1938
287Quadtree encoding (a simple compression algorithm)
1293
288An enormous factorial
1487
289Eulerian Cycles
429
290Digital Signature
886
291Panaitopol Primes
1284
292Pythagorean Polygons
515
293Pseudo-Fortunate Numbers
2684
294Sum of digits - experience #23
817
295Lenticular holes
408
296Angular Bisector and Tangent
514
297Zeckendorf Representation
2541
298Selective Amnesia
594
299Three similar triangles
552
300Protein folding
987