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Problems


IDDescription / TitleSolved By
51Prime digit replacements
15693
52Permuted multiples
34514
53Combinatoric selections
31361
54Poker hands
17310
55Lychrel numbers
28182
56Powerful digit sum
30293
57Square root convergents
20639
58Spiral primes
20091
59XOR decryption
21655
60Prime pair sets
12438
61Cyclical figurate numbers
12480
62Cubic permutations
15410
63Powerful digit counts
22114
64Odd period square roots
10974
65Convergents of e
15264
66Diophantine equation
9708
67Maximum path sum II
51124
68Magic 5-gon ring
10285
69Totient maximum
17695
70Totient permutation
11458
71Ordered fractions
14831
72Counting fractions
11401
73Counting fractions in a range
13509
74Digit factorial chains
13753
75Singular integer right triangles
8975
76Counting summations
14932
77Prime summations
9441
78Coin partitions
8268
79Passcode derivation
24642
80Square root digital expansion
10140
81Path sum: two ways
18103
82Path sum: three ways
10888
83Path sum: four ways
9207
84Monopoly odds
6217
85Counting rectangles
12912
86Cuboid route
6374
87Prime power triples
10688
88Product-sum numbers
4668
89Roman numerals
11417
90Cube digit pairs
5430
91Right triangles with integer coordinates
7941
92Square digit chains
21805
93Arithmetic expressions
5710
94Almost equilateral triangles
5983
95Amicable chains
7073
96Su Doku
8570
97Large non-Mersenne prime
25855
98Anagramic squares
5472
99Largest exponential
16047
100Arranged probability
7971