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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
856354
2Even Fibonacci Numbers
684542
3Largest Prime Factor
515637
4Largest Palindrome Product
455776
5Smallest Multiple
442215
6Sum Square Difference
447160
710 001st Prime
389680
8Largest Product in a Series
331745
9Special Pythagorean Triplet
337308
10Summation of Primes
316625
11Largest Product in a Grid
237057
12Highly Divisible Triangular Number
233413
13Large Sum
234147
14Longest Collatz Sequence
238520
15Lattice Paths
202324
16Power Digit Sum
236826
17Number Letter Counts
169686
18Maximum Path Sum I
164028
19Counting Sundays
153796
20Factorial Digit Sum
207003
21Amicable Numbers
169126
22Names Scores
155863
23Non-Abundant Sums
128483
24Lexicographic Permutations
137638
25$1000$-digit Fibonacci Number
175347
26Reciprocal Cycles
104613
27Quadratic Primes
108131
28Number Spiral Diagonals
126855
29Distinct Powers
127847
30Digit Fifth Powers
132612
31Coin Sums
104400
32Pandigital Products
88988
33Digit Cancelling Fractions
88835
34Digit Factorials
114986
35Circular Primes
103014
36Double-base Palindromes
107550
37Truncatable Primes
90951
38Pandigital Multiples
78160
39Integer Right Triangles
89894
40Champernowne's Constant
96961
41Pandigital Prime
84311
42Coded Triangle Numbers
89897
43Sub-string Divisibility
74300
44Pentagon Numbers
72861
45Triangular, Pentagonal, and Hexagonal
86323
46Goldbach's Other Conjecture
76414
47Distinct Primes Factors
71897
48Self Powers
123043
49Prime Permutations
71500
50Consecutive Prime Sum
76590