There're a lot of explanations of the unlucky number 13.
https://en.wikipedia.org/wiki/13_%28number%29
I'm happy with it.
There's more in the picture that wonders me. Not on the technical site, but what it registrated.
Small letterbox. In Holland they're much bigger.
The man is either very small or is sitting. But sitting en face there seem little space left between him and the door for his legs.
I see 2 locks in his door, placed in different ways.
George
The number 13 is painted over a non flat surface, making it difficult to paint it.