“…So far, we have obtained a sequence of triplets {(k j , m j , n j )} j≥1 , k j = (a j , 1, a j+1 ), m j = (a j+1 , −1, a j ), n j = (a j + a j+1 , 0, a j + a j+1 ), for which k j + m j = n j , n j ∈ L (1,0,1) , and by the above construction of {a j }, the curve Γ(k j , m j , n j ) passes through (1,1). (Given the sequence {a j } defined by (4.12), one can also show directly without using the theory of Pell's equation that (x, y) = (a j , a j+1 ) satisfies (4.10), and hence (1, 1) ∈ Γ(k j , m j , n j ), by an induction on j.…”