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Problems Archives

The problems archives table shows problems 1 to 713. 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
51Prime digit replacements
32295
52Permuted multiples
63259
53Combinatoric selections
57104
54Poker hands
34590
55Lychrel numbers
51994
56Powerful digit sum
56393
57Square root convergents
39935
58Spiral primes
38551
59XOR decryption
39689
60Prime pair sets
25312
61Cyclical figurate numbers
24168
62Cubic permutations
29940
63Powerful digit counts
41556
64Odd period square roots
20934
65Convergents of e
28551
66Diophantine equation
18563
67Maximum path sum II
93508
68Magic 5-gon ring
19648
69Totient maximum
33207
70Totient permutation
21076
71Ordered fractions
27934
72Counting fractions
21170
73Counting fractions in a range
23858
74Digit factorial chains
25449
75Singular integer right triangles
16925
76Counting summations
27278
77Prime summations
18058
78Coin partitions
15830
79Passcode derivation
39630
80Square root digital expansion
18784
81Path sum: two ways
32960
82Path sum: three ways
20058
83Path sum: four ways
17161
84Monopoly odds
11817
85Counting rectangles
23491
86Cuboid route
11867
87Prime power triples
19819
88Product-sum numbers
9338
89Roman numerals
20226
90Cube digit pairs
10469
91Right triangles with integer coordinates
14539
92Square digit chains
39986
93Arithmetic expressions
10971
94Almost equilateral triangles
11478
95Amicable chains
13363
96Su Doku
16118
97Large non-Mersenne prime
41781
98Anagramic squares
10557
99Largest exponential
29183
100Arranged probability
15286