Question 77
Consider the sequence
$$
y_{1} = y_{2} = 1, \quad y_{n+2} = (4k - 5) y_{n+1} - y_{n} + 4 - 2k, \quad n \geq 1
$$
Find all integers $k$ such that any term of the sequence is a perfect square.
$$
y_{1} = y_{2} = 1, \quad y_{n+2} = (4k - 5) y_{n+1} - y_{n} + 4 - 2k, \quad n \geq 1
$$
Find all integers $k$ such that any term of the sequence is a perfect square.