109 - L'énigme de Moriarty

[Ced]

"Cherche le 13ème premier" : Il parle du 13ème nombre

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41.

[Stef Bého]

You have to pick up the 13th prime number:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41

The answer is 41.