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
851815
2Even Fibonacci Numbers
681256
3Largest Prime Factor
513729
4Largest Palindrome Product
454142
5Smallest Multiple
440655
6Sum Square Difference
445682
710 001st Prime
388399
8Largest Product in a Series
330975
9Special Pythagorean Triplet
336475
10Summation of Primes
315880
11Largest Product in a Grid
236845
12Highly Divisible Triangular Number
233154
13Large Sum
233923
14Longest Collatz Sequence
238307
15Lattice Paths
202255
16Power Digit Sum
236628
17Number Letter Counts
169708
18Maximum Path Sum I
164125
19Counting Sundays
153891
20Factorial Digit Sum
207057
21Amicable Numbers
169201
22Names Scores
155874
23Non-Abundant Sums
128677
24Lexicographic Permutations
137798
25$1000$-digit Fibonacci Number
175390
26Reciprocal Cycles
104809
27Quadratic Primes
108295
28Number Spiral Diagonals
127009
29Distinct Powers
127967
30Digit Fifth Powers
132778
31Coin Sums
104542
32Pandigital Products
89144
33Digit Cancelling Fractions
89009
34Digit Factorials
115161
35Circular Primes
103162
36Double-base Palindromes
107744
37Truncatable Primes
91115
38Pandigital Multiples
78298
39Integer Right Triangles
90053
40Champernowne's Constant
97082
41Pandigital Prime
84427
42Coded Triangle Numbers
90071
43Sub-string Divisibility
74439
44Pentagon Numbers
72993
45Triangular, Pentagonal, and Hexagonal
86488
46Goldbach's Other Conjecture
76546
47Distinct Primes Factors
72010
48Self Powers
123148
49Prime Permutations
71595
50Consecutive Prime Sum
76727