RSS Feedsecure_iconYou are currently using a secure connection

Problems Archives

The problems archives table shows problems 1 to 495. If you would like to tackle the 10 most recently published problems then go to Recent problems.
Click the description/title of the problem to view details and submit your answer.


IDDescription / TitleSolved By
1Multiples of 3 and 5
442186
2Even Fibonacci numbers
363504
3Largest prime factor
264525
4Largest palindrome product
239425
5Smallest multiple
252282
6Sum square difference
254099
710001st prime
217759
8Largest product in a series
190060
9Special Pythagorean triplet
189073
10Summation of primes
173545
11Largest product in a grid
129218
12Highly divisible triangular number
117845
13Large sum
124424
14Longest Collatz sequence
122384
15Lattice paths
102007
16Power digit sum
127072
17Number letter counts
83979
18Maximum path sum I
81771
19Counting Sundays
75646
20Factorial digit sum
114723
21Amicable numbers
81264
22Names scores
75811
23Non-abundant sums
57291
24Lexicographic permutations
65279
251000-digit Fibonacci number
88480
26Reciprocal cycles
46734
27Quadratic primes
49187
28Number spiral diagonals
64298
29Distinct powers
59063
30Digit fifth powers
62551
31Coin sums
46697
32Pandigital products
39945
33Digit cancelling fractions
41028
34Digit factorials
54353
35Circular primes
49579
36Double-base palindromes
52515
37Truncatable primes
42120
38Pandigital multiples
35809
39Integer right triangles
41533
40Champernowne's constant
46320
41Pandigital prime
38769
42Coded triangle numbers
44025
43Sub-string divisibility
33256
44Pentagon numbers
32020
45Triangular, pentagonal, and hexagonal
41791
46Goldbach's other conjecture
34149
47Distinct primes factors
32550
48Self powers
69007
49Prime permutations
32380
50Consecutive prime sum
34752