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Problems Archives

The problems archives table shows problems 1 to 699. 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
1207
252Convex Holes
733
253Tidying up
908
254Sums of Digit Factorials
828
255Rounded Square Roots
763
256Tatami-Free Rooms
646
257Angular Bisectors
599
258A lagged Fibonacci sequence
1409
259Reachable Numbers
1345
260Stone Game
1161
261Pivotal Square Sums
593
262Mountain Range
624
263An engineers' dream come true
906
264Triangle Centres
502
265Binary Circles
3822
266Pseudo Square Root
1510
267Billionaire
3043
268Counting numbers with at least four distinct prime factors less than 100
1278
269Polynomials with at least one integer root
599
270Cutting Squares
562
271Modular Cubes, part 1
2107
272Modular Cubes, part 2
827
273Sum of Squares
1205
274Divisibility Multipliers
1268
275Balanced Sculptures
534
276Primitive Triangles
948
277A Modified Collatz sequence
2886
278Linear Combinations of Semiprimes
904
279Triangles with integral sides and an integral angle
613
280Ant and seeds
908
281Pizza Toppings
833
282The Ackermann function
869
283Integer sided triangles for which the area/perimeter ratio is integral
575
284Steady Squares
1111
285Pythagorean odds
1061
286Scoring probabilities
1898
287Quadtree encoding (a simple compression algorithm)
1278
288An enormous factorial
1461
289Eulerian Cycles
419
290Digital Signature
870
291Panaitopol Primes
1255
292Pythagorean Polygons
506
293Pseudo-Fortunate Numbers
2622
294Sum of digits - experience #23
803
295Lenticular holes
403
296Angular Bisector and Tangent
511
297Zeckendorf Representation
2507
298Selective Amnesia
590
299Three similar triangles
544
300Protein folding
966