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Problems Archives

  • Problem 699 will be accessible in 3 hours, 55 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
101Optimum polynomial
10198
102Triangle containment
20070
103Special subset sums: optimum
7107
104Pandigital Fibonacci ends
14804
105Special subset sums: testing
7111
106Special subset sums: meta-testing
5649
107Minimal network
9930
108Diophantine reciprocals I
11533
109Darts
7262
110Diophantine reciprocals II
7269
111Primes with runs
6417
112Bouncy numbers
22690
113Non-bouncy numbers
10025
114Counting block combinations I
9809
115Counting block combinations II
8944
116Red, green or blue tiles
10997
117Red, green, and blue tiles
10083
118Pandigital prime sets
6134
119Digit power sum
11211
120Square remainders
12601
121Disc game prize fund
8780
122Efficient exponentiation
6949
123Prime square remainders
10508
124Ordered radicals
12557
125Palindromic sums
12345
126Cuboid layers
4143
127abc-hits
5530
128Hexagonal tile differences
4408
129Repunit divisibility
5602
130Composites with prime repunit property
5262
131Prime cube partnership
6590
132Large repunit factors
5666
133Repunit nonfactors
4915
134Prime pair connection
6246
135Same differences
5677
136Singleton difference
4980
137Fibonacci golden nuggets
4838
138Special isosceles triangles
5142
139Pythagorean tiles
4985
140Modified Fibonacci golden nuggets
3789
141Investigating progressive numbers, n, which are also square
3418
142Perfect Square Collection
5183
143Investigating the Torricelli point of a triangle
2387
144Investigating multiple reflections of a laser beam
5560
145How many reversible numbers are there below one-billion?
15265
146Investigating a Prime Pattern
4433
147Rectangles in cross-hatched grids
2647
148Exploring Pascal's triangle
4567
149Searching for a maximum-sum subsequence
4308
150Searching a triangular array for a sub-triangle having minimum-sum
3526