RSS FeedUse secure connection

Problems


IDDescription / TitleSolved By
1
Multiples of 3 and 5
293180
2
Even Fibonacci numbers
241688
3
Largest prime factor
175606
4
Largest palindrome product
160877
5
Smallest multiple
175753
6
Sum square difference
177327
7
10001st prime
150710
8
Largest product in a series
133164
9
Special Pythagorean triplet
132754
10
Summation of primes
121035
11
Largest product in a grid
90994
12
Highly divisible triangular number
81310
13
Large sum
88209
14
Longest Collatz sequence
86013
15
Lattice paths
71196
16
Power digit sum
92094
17
Number letter counts
59233
18
Maximum path sum I
58875
19
Counting Sundays
53899
20
Factorial digit sum
86345
21
Amicable numbers
58262
22
Names scores
54375
23
Non-abundant sums
40456
24
Lexicographic permutations
47444
25
1000-digit Fibonacci number
64484
26
Reciprocal cycles
33371
27
Quadratic primes
35272
28
Number spiral diagonals
48614
29
Distinct powers
42701
30
Digit fifth powers
45613
31
Coin sums
32832
32
Pandigital products
28532
33
Digit canceling fractions
29967
34
Digit factorials
40058
35
Circular primes
36661
36
Double-base palindromes
39391
37
Truncatable primes
30672
38
Pandigital multiples
25955
39
Integer right triangles
30182
40
Champernowne's constant
34019
41
Pandigital prime
28314
42
Coded triangle numbers
33139
43
Sub-string divisibility
23608
44
Pentagon numbers
22869
45
Triangular, pentagonal, and hexagonal
31519
46
Goldbach's other conjecture
24160
47
Distinct primes factors
23678
48
Self powers
54149
49
Prime permutations
23159
50
Consecutive prime sum
25014