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Problems Archives

The problems archives table shows problems 1 to 679. 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
1166
252Convex Holes
713
253Tidying up
885
254Sums of Digit Factorials
812
255Rounded Square Roots
746
256Tatami-Free Rooms
625
257Angular Bisectors
579
258A lagged Fibonacci sequence
1359
259Reachable Numbers
1315
260Stone Game
1130
261Pivotal Square Sums
574
262Mountain Range
611
263An engineers' dream come true
883
264Triangle Centres
485
265Binary Circles
3750
266Pseudo Square Root
1472
267Billionaire
2964
268Counting numbers with at least four distinct prime factors less than 100
1242
269Polynomials with at least one integer root
584
270Cutting Squares
547
271Modular Cubes, part 1
2048
272Modular Cubes, part 2
803
273Sum of Squares
1167
274Divisibility Multipliers
1239
275Balanced Sculptures
516
276Primitive Triangles
925
277A Modified Collatz sequence
2814
278Linear Combinations of Semiprimes
880
279Triangles with integral sides and an integral angle
590
280Ant and seeds
887
281Pizza Toppings
798
282The Ackermann function
840
283Integer sided triangles for which the area/perimeter ratio is integral
556
284Steady Squares
1083
285Pythagorean odds
1026
286Scoring probabilities
1847
287Quadtree encoding (a simple compression algorithm)
1244
288An enormous factorial
1416
289Eulerian Cycles
407
290Digital Signature
846
291Panaitopol Primes
1221
292Pythagorean Polygons
495
293Pseudo-Fortunate Numbers
2567
294Sum of digits - experience #23
782
295Lenticular holes
395
296Angular Bisector and Tangent
498
297Zeckendorf Representation
2447
298Selective Amnesia
578
299Three similar triangles
532
300Protein folding
937