[seqfan] Coins puzzle and a sequence

[Tanya Khovanova]

Hello SeqFans,

Here is a puzzle I love very much:

You have 6 coins weighing 1, 2, 3, 4, 5 and 6 grams that look the same, except for their labels. The number (1, 2, 3, 4, 5, 6) on the top of each coin should correspond to its weight. How can you determine whether all the numbers are correct, using the balance scale only twice?

I haven't heard the correct solution from anyone yet.

I wrote an essay on the related sequence:
http://blog.tanyakhovanova.com/?p=148

I didn't submit the sequence as I am not sure about a(7), a(8) and a(9).

Tanya