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Problems Archives

The problems archives table shows problems 1 to 632. 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
27925
52Permuted multiples
56022
53Combinatoric selections
50482
54Poker hands
29950
55Lychrel numbers
45929
56Powerful digit sum
49777
57Square root convergents
35007
58Spiral primes
33876
59XOR decryption
35410
60Prime pair sets
21861
61Cyclical figurate numbers
21174
62Cubic permutations
26157
63Powerful digit counts
36551
64Odd period square roots
18377
65Convergents of e
25275
66Diophantine equation
16332
67Maximum path sum II
83409
68Magic 5-gon ring
17287
69Totient maximum
28940
70Totient permutation
18649
71Ordered fractions
24489
72Counting fractions
18656
73Counting fractions in a range
21195
74Digit factorial chains
22454
75Singular integer right triangles
14917
76Counting summations
24084
77Prime summations
15867
78Coin partitions
13974
79Passcode derivation
36054
80Square root digital expansion
16682
81Path sum: two ways
29382
82Path sum: three ways
17812
83Path sum: four ways
15234
84Monopoly odds
10396
85Counting rectangles
20882
86Cuboid route
10497
87Prime power triples
17498
88Product-sum numbers
8141
89Roman numerals
18187
90Cube digit pairs
9153
91Right triangles with integer coordinates
12848
92Square digit chains
35799
93Arithmetic expressions
9633
94Almost equilateral triangles
10053
95Amicable chains
11741
96Su Doku
14125
97Large non-Mersenne prime
37939
98Anagramic squares
9280
99Largest exponential
25905
100Arranged probability
13397