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Problems Archives

• Problem 699 will be accessible in 4 hours, 36 minutes (Sunday, 26th January 2020, 10:00 am)

The problems archives table shows problems 1 to 688. 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
201Subsets with a unique sum
2016
202Laserbeam
2215
203Squarefree Binomial Coefficients
8328
204Generalised Hamming Numbers
6631
205Dice Game
13704
206Concealed Square
22361
207Integer partition equations
4303
208Robot Walks
1542
209Circular Logic
2215
210Obtuse Angled Triangles
1498
211Divisor Square Sum
3714
212Combined Volume of Cuboids
1200
213Flea Circus
2047
214Totient Chains
4669
215Crack-free Walls
3327
216Investigating the primality of numbers of the form 2n2-1
3619
217Balanced Numbers
1321
218Perfect right-angled triangles
2741
219Skew-cost coding
1318
220Heighway Dragon
1987
221Alexandrian Integers
1836
222Sphere Packing
1868
223Almost right-angled triangles I
1315
224Almost right-angled triangles II
1059
225Tribonacci non-divisors
4032
226A Scoop of Blancmange
1550
227The Chase
1888
228Minkowski Sums
1167
229Four Representations using Squares
1315
230Fibonacci Words
2599
231The prime factorisation of binomial coefficients
4892
232The Race
1558
233Lattice points on a circle
1995
234Semidivisible numbers
2953
235An Arithmetic Geometric sequence
4530
236Luxury Hampers
813
237Tours on a 4 x n playing board
1376
238Infinite string tour
842
239Twenty-two Foolish Primes
1605
240Top Dice
1944
241Perfection Quotients
806
242Odd Triplets
910
243Resilience
8648
244Sliders
1155
245Coresilience
721
246Tangents to an ellipse
696
247Squares under a hyperbola
1282
248Numbers for which Eulerâ€™s totient function equals 13!
1133
249Prime Subset Sums
2255
250250250
2637