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Problems Archives

The problems archives table shows problems 1 to 670. 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
1156
252Convex Holes
705
253Tidying up
872
254Sums of Digit Factorials
806
255Rounded Square Roots
739
256Tatami-Free Rooms
617
257Angular Bisectors
569
258A lagged Fibonacci sequence
1341
259Reachable Numbers
1307
260Stone Game
1121
261Pivotal Square Sums
567
262Mountain Range
604
263An engineers' dream come true
878
264Triangle Centres
477
265Binary Circles
3711
266Pseudo Square Root
1458
267Billionaire
2928
268Counting numbers with at least four distinct prime factors less than 100
1225
269Polynomials with at least one integer root
576
270Cutting Squares
540
271Modular Cubes, part 1
2025
272Modular Cubes, part 2
786
273Sum of Squares
1151
274Divisibility Multipliers
1231
275Balanced Sculptures
509
276Primitive Triangles
910
277A Modified Collatz sequence
2778
278Linear Combinations of Semiprimes
865
279Triangles with integral sides and an integral angle
586
280Ant and seeds
879
281Pizza Toppings
793
282The Ackermann function
831
283Integer sided triangles for which the area/perimeter ratio is integral
551
284Steady Squares
1074
285Pythagorean odds
1012
286Scoring probabilities
1829
287Quadtree encoding (a simple compression algorithm)
1227
288An enormous factorial
1403
289Eulerian Cycles
404
290Digital Signature
838
291Panaitopol Primes
1210
292Pythagorean Polygons
491
293Pseudo-Fortunate Numbers
2536
294Sum of digits - experience #23
773
295Lenticular holes
393
296Angular Bisector and Tangent
493
297Zeckendorf Representation
2421
298Selective Amnesia
576
299Three similar triangles
525
300Protein folding
925