This is a proof based problem added for learning purposes and does not accept submissions.
You can view the solution by clicking on the solution tab.
You can view the solution by clicking on the solution tab.
Prove that, there is a sequence of $2023$ distinct positive integers such that the sum of the squares of any two consecutive terms is a perfect square itself.
Let $(a_k)_{1\leq k\leq 2023}$ be the required sequence.
\[a_k=3^{2024-k}\cdot 4^{k-1}\]
Here, the sum of the squares of two consecutive terms \[a_k^2+a_{k+1}^2=(3^{2024-k}\cdot 4^{k-1})^2+(3^{2023-k}\cdot 4^{k})^2=(3^{2023-k}\cdot 4^{k-1})^2(3^2+4^2)=(3^{2023-k}\cdot 4^{k-1}\cdot 5)^2\]
Which is a square.
So, such a sequence exists.