Problem

[Roberto Tauraso]

Dear seqfans,
I'm intersted in the following problem:

Find all the positive integers n such that
the set {1,2,..2n} can be arranged into
n disjoint pairs so that for any pair the
sum of the two numbers is a perfect square.

I think that this "matching" can't be done only
for the numbers 1,2,3,5,6,10 and 11.
Is there anybody that has already heard about it?
Please let me know any reference or proof.

Bye,
Roberto Tauraso

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Roberto Tauraso
Dipartimento di Matematica
Universita' di Roma "Tor Vergata", Italy
e-mail: tauraso at mat.uniroma2.it
www.mat.uniroma2.it/~tauraso
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