Search Problems   RSS Feed

Problem Archives

The problems archives table shows problems 1 to 1004. 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
852241
2Even Fibonacci Numbers
681552
3Largest Prime Factor
513897
4Largest Palindrome Product
454289
5Smallest Multiple
440803
6Sum Square Difference
445802
710 001st Prime
388487
8Largest Product in a Series
331032
9Special Pythagorean Triplet
336520
10Summation of Primes
315906
11Largest Product in a Grid
236832
12Highly Divisible Triangular Number
233137
13Large Sum
233911
14Longest Collatz Sequence
238296
15Lattice Paths
202232
16Power Digit Sum
236632
17Number Letter Counts
169687
18Maximum Path Sum I
164090
19Counting Sundays
153869
20Factorial Digit Sum
207027
21Amicable Numbers
169184
22Names Scores
155880
23Non-Abundant Sums
128644
24Lexicographic Permutations
137765
25$1000$-digit Fibonacci Number
175370
26Reciprocal Cycles
104776
27Quadratic Primes
108276
28Number Spiral Diagonals
126986
29Distinct Powers
127951
30Digit Fifth Powers
132740
31Coin Sums
104521
32Pandigital Products
89119
33Digit Cancelling Fractions
88989
34Digit Factorials
115128
35Circular Primes
103133
36Double-base Palindromes
107714
37Truncatable Primes
91092
38Pandigital Multiples
78277
39Integer Right Triangles
90035
40Champernowne's Constant
97052
41Pandigital Prime
84409
42Coded Triangle Numbers
90051
43Sub-string Divisibility
74420
44Pentagon Numbers
72973
45Triangular, Pentagonal, and Hexagonal
86460
46Goldbach's Other Conjecture
76521
47Distinct Primes Factors
71987
48Self Powers
123124
49Prime Permutations
71584
50Consecutive Prime Sum
76700