ID NAME QUALITY USERS ACC % DIFFICULTY C I
30757 Ada and Carrot   6 127
17
34
32029 Ada and Connections   6 69
24
24
32840 Ada and Digits   15 167
20
18
32949 Ada and Digits 2   4 70
28
28
30739 Ada and Manure   17 297
11
22
30755 Ada and GCD   20 431
28
15
30691 Ada and Diary   1 55
1
1
30737 Ada and Homework   3 63
34
34
32683 Ada and Kohlrabi   5 66
30
13
32059 Ada and Taxes   15 102
23
22
5151 Alice’s Cube   8 501
24
21
10232 Distinct Primes   83 5763
10
9
4556 Think I will Buy Me a Football Team   30 2163
7
11
5451 Not So Flat After All   9 1116
11
10
13753 Amazing Prime Sequence   61 3299
11
12
30826 Bernoulli numbers   4 7
23
12
31066 Number Breaking   10 743
13
12
21357 Crucial Equation   79 5982
4
9
3505 Prime Number Theorem   25 1519
14
13
9032 Cube Free Numbers   65 4116
12
11
526 Divisors   37 1677
14
14
530 Divisors 2   10 898
14
17
22403 Divisors of factorial   70 1903
14
14
74 Divisor Summation   92 15743
8
10
23963 Easy Factorials   10 112
27
26
4141 Euler Totient Function   144 11387
8
11
22382 Euler Totient Function Depth   24 371
15
16
4942 Integer Factorization (15 digits)   45 3353
11
11
33046 Factorial Modulo Prime   3 27
45
39
25584 Factorial Modulo   25 407
10
15
25067 Fibonacci Polynomial   8 208
10
20
5970 Finding Primes   22 1324
16
15
6264 Rank of a Fraction   4 129
12
34
5978 Frequent Prime Ranges   9 687
13
13
3871 GCD Extreme   77 2461
18
26
41657 GCD Goodness   1 20
17
17
26045 GCD OF MATRIX (hard)   3 115
47
28
41507 GCD Product Sum   4 35
5
21
12005 Grass Planting   9 485
32
17
18202 HUGE GCD   17 660
14
13
4164 A conjecture of Paul Erdős   23 1993
16
14
12241 Classification from Erdős and Selfridge   5 27
28
28
27195 Find The Number   7 207
20
17
6221 Increasing Powers of K   4 350
24
34
6256 Inversion Count   526 16637
16
18
40083 Just Primes   10 105
15
17
40084 Just Primes II   6 20
34
26
12183 Help the Commander in Chief   46 905
15
16
34812 Kth Power Summation   5 53
23
17
3442 The last digit   188 29165
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