ID NAME QUALITY USERS ACC % DIFFICULTY C I
30757 Ada and Carrot   6 129
17
34
32029 Ada and Connections   6 69
24
24
32840 Ada and Digits   15 168
20
18
32949 Ada and Digits 2   5 71
30
30
30739 Ada and Manure   18 301
11
22
30755 Ada and GCD   20 436
28
15
30691 Ada and Diary   2 56
9
9
30737 Ada and Homework   3 63
34
34
32683 Ada and Kohlrabi   5 67
30
13
32059 Ada and Taxes   16 103
23
23
5151 Alice’s Cube   8 501
24
21
10232 Distinct Primes   84 5822
10
9
4556 Think I will Buy Me a Football Team   30 2172
7
11
5451 Not So Flat After All   9 1121
11
10
13753 Amazing Prime Sequence   61 3316
11
12
30826 Bernoulli numbers   4 7
23
12
31066 Number Breaking   10 753
13
12
21357 Crucial Equation   80 6164
4
9
3505 Prime Number Theorem   25 1524
14
13
9032 Cube Free Numbers   65 4125
12
11
526 Divisors   38 1692
14
13
530 Divisors 2   10 909
12
16
22403 Divisors of factorial   71 1925
14
14
74 Divisor Summation   92 16055
8
10
23963 Easy Factorials   10 112
27
26
4141 Euler Totient Function   145 11599
8
11
22382 Euler Totient Function Depth   24 381
15
16
4942 Integer Factorization (15 digits)   45 3446
11
11
33046 Factorial Modulo Prime   4 29
46
42
25584 Factorial Modulo   25 408
10
15
25067 Fibonacci Polynomial   8 222
10
20
5970 Finding Primes   22 1332
16
15
6264 Rank of a Fraction   4 129
12
34
5978 Frequent Prime Ranges   10 697
14
14
3871 GCD Extreme   79 2671
19
26
41657 GCD Goodness   2 23
17
26
26045 GCD OF MATRIX (hard)   3 122
47
28
41507 GCD Product Sum   6 43
6
23
12005 Grass Planting   11 522
32
19
18202 HUGE GCD   17 675
14
13
4164 A conjecture of Paul Erdős   23 2216
16
14
12241 Classification from Erdős and Selfridge   5 27
28
28
27195 Find The Number   7 211
20
17
6221 Increasing Powers of K   4 352
24
34
6256 Inversion Count   532 17127
16
18
40083 Just Primes   11 110
15
17
40084 Just Primes II   7 23
34
30
12183 Help the Commander in Chief   46 907
15
16
34812 Kth Power Summation   6 54
25
19
3442 The last digit   189 29531
9
8

#number-theory

The problem involves number theory, a branch of pure mathematics

https://en.wikipedia.org/wiki/Number_theory http://mathworld.wolfram.com/NumberTheory.html http://www.math.brown.edu/~jhs/frintch1ch6.pdf http://www.britannica.com/topic/number-theory