20 shortest unsolved problems

# Problem Difficulty Length
1 GCD Sum 2 5.5 320 chars
2 Gauss Squares 4.1 334 chars
3 Emag Eht Htiw Em Pleh 1.9 379 chars
4 Almost Pythagorean 6.1 389 chars
5 Datum 1.5 420 chars
6 Division 6.7 435 chars
7 Inverse Totient 6.8 451 chars
8 Yet Another Divisor Problem 8.0 491 chars
9 Brahmagupta-Fibonacci 3.3 505 chars
10 Danish Date Format 1.5 512 chars
11 Primitive Roots 6.7 522 chars
12 How many 0's? 3.1 554 chars
13 Multiplication Over Symmetric Difference 6.2 570 chars
14 Suffidromes 7.9 590 chars
15 Early Orders 5.6 594 chars
16 EvenOdd 5.9 595 chars
17 Prime Count 2.8 - 7.9 607 chars
18 Classical Counting 7.7 618 chars
19 Poker Hand 1.4 619 chars
20 Political Distance 1.9 621 chars
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