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Problems


IDDescription / TitleSolved By
51
Prime digit replacements
13002
52
Permuted multiples
30024
53
Combinatoric selections
27321
54
Poker hands
14569
55
Lychrel numbers
24402
56
Powerful digit sum
26012
57
Square root convergents
17495
58
Spiral primes
16958
59
XOR decryption
18491
60
Prime pair sets
10365
61
Cyclical figurate numbers
10480
62
Cubic permutations
12924
63
Powerful digit counts
19035
64
Odd period square roots
9197
65
Convergents of e
12668
66
Diophantine equation
8203
67
Maximum path sum II
43261
68
Magic 5-gon ring
8578
69
Totient maximum
15313
70
Totient permutation
9741
71
Ordered fractions
12854
72
Counting fractions
9704
73
Counting fractions in a range
11785
74
Digit factorial chains
11657
75
Singular integer right triangles
7547
76
Counting summations
13021
77
Prime summations
7890
78
Coin partitions
6901
79
Passcode derivation
22160
80
Square root digital expansion
8635
81
Path sum: two ways
15302
82
Path sum: three ways
9213
83
Path sum: four ways
7720
84
Monopoly odds
5273
85
Counting rectangles
11058
86
Cuboid route
5312
87
Prime power triples
9018
88
Product-sum numbers
3857
89
Roman numerals
9382
90
Cube digit pairs
4546
91
Right triangles with integer coordinates
6765
92
Square digit chains
18320
93
Arithmetic expressions
4804
94
Almost equilateral triangles
5035
95
Amicable chains
5939
96
Su Doku
7339
97
Large non-Mersenne prime
23739
98
Anagramic squares
4578
99
Largest exponential
13882
100
Arranged probability
6642