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Problems


IDDescription / TitleSolved By
51Prime digit replacements
15721
52Permuted multiples
34567
53Combinatoric selections
31403
54Poker hands
17335
55Lychrel numbers
28224
56Powerful digit sum
30346
57Square root convergents
20670
58Spiral primes
20129
59XOR decryption
21690
60Prime pair sets
12456
61Cyclical figurate numbers
12497
62Cubic permutations
15431
63Powerful digit counts
22150
64Odd period square roots
10991
65Convergents of e
15286
66Diophantine equation
9721
67Maximum path sum II
51197
68Magic 5-gon ring
10299
69Totient maximum
17715
70Totient permutation
11473
71Ordered fractions
14848
72Counting fractions
11414
73Counting fractions in a range
13522
74Digit factorial chains
13768
75Singular integer right triangles
8985
76Counting summations
14949
77Prime summations
9452
78Coin partitions
8282
79Passcode derivation
24675
80Square root digital expansion
10154
81Path sum: two ways
18133
82Path sum: three ways
10902
83Path sum: four ways
9219
84Monopoly odds
6225
85Counting rectangles
12928
86Cuboid route
6380
87Prime power triples
10707
88Product-sum numbers
4675
89Roman numerals
11430
90Cube digit pairs
5438
91Right triangles with integer coordinates
7949
92Square digit chains
21829
93Arithmetic expressions
5720
94Almost equilateral triangles
5990
95Amicable chains
7080
96Su Doku
8576
97Large non-Mersenne prime
25878
98Anagramic squares
5475
99Largest exponential
16071
100Arranged probability
7984