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Problem Archives

The problems archives table shows problems 1 to 1000. If you would like to tackle the 10 most recently published problems, go to Recent problems.



ID

 Title
Solved By
1Multiples of 3 or 5
856331
2Even Fibonacci Numbers
684532
3Largest Prime Factor
515626
4Largest Palindrome Product
455765
5Smallest Multiple
442207
6Sum Square Difference
447156
710 001st Prime
389675
8Largest Product in a Series
331740
9Special Pythagorean Triplet
337305
10Summation of Primes
316619
11Largest Product in a Grid
237053
12Highly Divisible Triangular Number
233409
13Large Sum
234141
14Longest Collatz Sequence
238514
15Lattice Paths
202319
16Power Digit Sum
236824
17Number Letter Counts
169685
18Maximum Path Sum I
164025
19Counting Sundays
153795
20Factorial Digit Sum
207002
21Amicable Numbers
169125
22Names Scores
155863
23Non-Abundant Sums
128483
24Lexicographic Permutations
137638
25$1000$-digit Fibonacci Number
175347
26Reciprocal Cycles
104610
27Quadratic Primes
108129
28Number Spiral Diagonals
126853
29Distinct Powers
127846
30Digit Fifth Powers
132611
31Coin Sums
104400
32Pandigital Products
88988
33Digit Cancelling Fractions
88834
34Digit Factorials
114986
35Circular Primes
103011
36Double-base Palindromes
107549
37Truncatable Primes
90948
38Pandigital Multiples
78160
39Integer Right Triangles
89894
40Champernowne's Constant
96960
41Pandigital Prime
84309
42Coded Triangle Numbers
89897
43Sub-string Divisibility
74297
44Pentagon Numbers
72861
45Triangular, Pentagonal, and Hexagonal
86321
46Goldbach's Other Conjecture
76414
47Distinct Primes Factors
71897
48Self Powers
123043
49Prime Permutations
71500
50Consecutive Prime Sum
76590