the sides of this type of primitive Pythagorean triple (PPT) then the solution to the Pell equation is given by the recursive formula with and with and with and . This sequence of PPTs forms the central stem (trunk) of the rooted ternary tree of PPTs. When it is the longer non-hypotenuse side and hypotenuse that differ by one, such as in then the complete solution for the PPT , , is and where integer is the generating parameter. It shows that all odd numbers (greater than 1) appear in this type of almost-isosceles PPT. This sequence of PPTs forms the right hand side outer stem of the rooted ternary tree of PPTs. Another property of this type of almost-isosceles PPT is that the sides are related such that for some integer . Or in other words is divisible by such as in . Fibonacci numbers in Pythagorean triples Starting with 5, every second Fibonacci number is the length of the hypotenuse of a right triangle with integer sides, or in other words, the largest number in a Pythagorean triple, obtained from the formula The sequence of Pythagorean triangles obtained from this formula has sides of lengths (3,4,5), (5,12,13), (16,30,34), (39,80,89), ... The middle side of each of these triangles is the sum of the three sides of the preceding triangle. Generalizations There are several ways to generalize the concept of Pythagorean triples. Pythagorean -tuple The expression is a Pythagorean -tuple for any tuple of positive integers with . The Pythagorean -tuple can be made primitive by dividing out by the largest common divisor of its values. Furthermore, any primitive Pythagorean -tuple can be found by this approach. Use to get a Pythagorean -tuple by the above formula and divide out by the largest common integer divisor, which is . Dividing out by the largest common divisor of these values gives the same primitive Pythagorean -tuple; and there is a one-to-one correspondence between tuples of setwise coprime positive integers satisfying and primitive Pythagorean -tuples. Examples of the relationship between setwise coprime values and primitive Pythagorean -tuples include: Consecutive squares Since the sum of consecutive squares beginning with is given by the formula, one may find values so that is a square, such as one by Hirschhorn where the number of terms is itself a square, and is any integer not divisible by 2 or 3. For the smallest case ,