list of classical problems


ID NAME QUALITY USERS ACC % DIFFICULTY C I
2 Prime Generator   619 77811 15.96
15
13
91 Two squares or not two squares   78 5987 24.53
11
14
134 Phony Primes   1 179 19.18
23
23
526 Divisors   37 1677 43.54
14
14
530 Divisors 2   10 898 52.65
14
17
3107 Odd Numbers of Divisors   27 1039 18.25
22
22
3166 Permutation Exponentiation   33 14.85
3442 The last digit   188 29166 26.96
9
8
3505 Prime Number Theorem   25 1519 28.00
14
13
3591 Patting Heads   3 636 35.07
17
17
3643 Traffic Network   89 2087 18.30
18
21
3871 GCD Extreme   77 2461 29.44
18
26
3932 Point Connection Game in a Circle   3 746 35.44
13
21
4141 Euler Totient Function   144 11387 38.36
8
11
4164 A conjecture of Paul Erdős   23 1993 45.20
16
14
4168 Square-free integers   12 602 43.71
13
19
4523 Binomial Coefficients   209 41.72
23
12
4556 Think I will Buy Me a Football Team   30 2163 44.97
7
11
4839 Ant   3 190 39.06
23
28
4942 Integer Factorization (15 digits)   45 3353 32.27
11
11
5107 Playing with Marbles   7 786 23.60
12
8
5151 Alice’s Cube   8 501 28.99
24
21
5451 Not So Flat After All   9 1116 42.57
11
10
5732 Paradox   42 1218 27.87
16
19
5970 Finding Primes   22 1324 27.84
16
15
5971 LCM Sum   80 3482 25.63
20
29
5978 Frequent Prime Ranges   9 687 29.18
13
13
6221 Increasing Powers of K   4 350 27.39
24
34
6256 Inversion Count   526 16638 31.53
16
18
6264 Rank of a Fraction   4 129 31.58
12
34
6285 Another Game With Numbers   31 1213 30.45
11
12
6288 Treeramids   15 1087 51.89
20
17
6294 Yodaness Level   74 3512 49.20
15
16
6450 PP numbers   10 869 41.82
10
6
6556 N DIV PHI_N   14 732 37.91
5
26
8238 N-Factorful   67 2458 26.43
17
16
9032 Cube Free Numbers   65 4116 31.68
12
11
9385 Strictly not a Prime   9 363 28.69
17
12
10050 Power Tower City   6 85 68.08
24
28
10232 Distinct Primes   83 5763 45.50
10
9
11736 Prime Time   25 2146 48.45
11
12
12005 Grass Planting   9 485 43.38
32
17
12183 Help the Commander in Chief   46 905 28.99
15
16
12241 Classification from Erdős and Selfridge   5 27 17.71
28
28
12933 n-divisors   59 2279 19.26
18
17
13753 Amazing Prime Sequence   61 3299 29.75
11
12
17125 Thor vs Frost Giants   1 187 28.90
39
28
17143 Make Psycho   2 223 24.98
34
9
18202 HUGE GCD   17 660 33.32
14
13
19308 LCM   8 384 18.70
17
24

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