Solution:
Suppose that such a permutation exists. Since {pi+i∣1≤i≤n} is a complete system of residues modulo n, we have ∑k=1nk≡∑i=1n(pi+i)≡∑i=1ni+∑i=1npi≡2∑k=1nk (mod n), hence ∑k=1nk=2n(n+1)≡0 (mod n), from which it follows that 2∤n.
Moreover, we have 2∑k=1nk2≡∑k=1n((pi+i)2+(pi−i)2)≡∑k=1n(2pi2+2i2)≡4∑k=1nk2, from which 2∑k=1nk2=3n(n+1)(2n+1)≡0 (mod n), hence 3∤n.
Therefore, we must have (n,6)=1.
On the other hand, if (n,6)=1 and pi≡2i (mod n), pi∈{1,…,n}, then (p1,p2,…,pn) is a permutation of the set {1,…,n} and satisfies the conditions, since {pi+i∣1≤i≤n}≡{3i∣1≤i≤n} and {pi−i∣1≤i≤n}≡{i∣1≤i≤n} (mod n) are complete systems of residues modulo n.