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Problems Archives

The problems archives table shows problems 1 to 751. 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.


ID

Description / TitleSolved By
251Cardano Triplets
1314
252Convex Holes
795
253Tidying up
971
254Sums of Digit Factorials
908
255Rounded Square Roots
818
256Tatami-Free Rooms
698
257Angular Bisectors
648
258A lagged Fibonacci sequence
1519
259Reachable Numbers
1434
260Stone Game
1244
261Pivotal Square Sums
646
262Mountain Range
677
263An engineers' dream come true
974
264Triangle Centres
529
265Binary Circles
4061
266Pseudo Square Root
1609
267Billionaire
3248
268Counting numbers with at least four distinct prime factors less than 100
1371
269Polynomials with at least one integer root
650
270Cutting Squares
611
271Modular Cubes, part 1
2265
272Modular Cubes, part 2
907
273Sum of Squares
1304
274Divisibility Multipliers
1345
275Balanced Sculptures
568
276Primitive Triangles
1027
277A Modified Collatz sequence
3096
278Linear Combinations of Semiprimes
992
279Triangles with integral sides and an integral angle
679
280Ant and seeds
972
281Pizza Toppings
905
282The Ackermann function
947
283Integer sided triangles for which the area/perimeter ratio is integral
601
284Steady Squares
1202
285Pythagorean odds
1143
286Scoring probabilities
2041
287Quadtree encoding (a simple compression algorithm)
1367
288An enormous factorial
1572
289Eulerian Cycles
462
290Digital Signature
924
291Panaitopol Primes
1364
292Pythagorean Polygons
539
293Pseudo-Fortunate Numbers
2826
294Sum of digits - experience #23
854
295Lenticular holes
425
296Angular Bisector and Tangent
542
297Zeckendorf Representation
2678
298Selective Amnesia
633
299Three similar triangles
584
300Protein folding
1042