PUZZLEBOXX

Start with 142857

Multiplying by 3 gives 428571.

Multiplying by 2 gives 285714.

Multiplying by 6 gives 857142.

Multiplying by 4 gives 571428.

Multiplying by 5 gives 714285.

You will notice that the number has rotated all the way round.

Now multiply it by 7. Wow!