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Problems Archives

The problems archives table shows problems 1 to 667. 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
29711
52Permuted multiples
58832
53Combinatoric selections
53094
54Poker hands
31846
55Lychrel numbers
48324
56Powerful digit sum
52396
57Square root convergents
36934
58Spiral primes
35767
59XOR decryption
37163
60Prime pair sets
23270
61Cyclical figurate numbers
22436
62Cubic permutations
27700
63Powerful digit counts
38562
64Odd period square roots
19448
65Convergents of e
26597
66Diophantine equation
17263
67Maximum path sum II
87532
68Magic 5-gon ring
18226
69Totient maximum
30643
70Totient permutation
19651
71Ordered fractions
25946
72Counting fractions
19708
73Counting fractions in a range
22308
74Digit factorial chains
23714
75Singular integer right triangles
15739
76Counting summations
25429
77Prime summations
16770
78Coin partitions
14719
79Passcode derivation
37531
80Square root digital expansion
17525
81Path sum: two ways
30814
82Path sum: three ways
18728
83Path sum: four ways
16011
84Monopoly odds
10955
85Counting rectangles
21957
86Cuboid route
11038
87Prime power triples
18433
88Product-sum numbers
8602
89Roman numerals
18986
90Cube digit pairs
9692
91Right triangles with integer coordinates
13534
92Square digit chains
37523
93Arithmetic expressions
10160
94Almost equilateral triangles
10630
95Amicable chains
12405
96Su Doku
14878
97Large non-Mersenne prime
39517
98Anagramic squares
9801
99Largest exponential
27240
100Arranged probability
14135