# Square number + square number = square number

Does there exist an infinitely long sequence ($$a_1, a_2, a_3, \dots$$), where each term of the sequence is a perfect square, $$a_n<a_{n+1}$$ is true for any positive integer $$n$$ and $$a_k+a_{k+1}$$ is a perfect square for any positive integer $$k$$?

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