
Singular Integer Right Triangles
It turns out that $\pu{12 cm}$ is the smallest length of wire that can be bent to form an integer sided right angle triangle in exactly one way, but there are many more examples.
- $\pu{\mathbf{12} \mathbf{cm} }$: $(3,4,5)$
- $\pu{\mathbf{24} \mathbf{cm} }$: $(6,8,10)$
- $\pu{\mathbf{30} \mathbf{cm} }$: $(5,12,13)$
- $\pu{\mathbf{36} \mathbf{cm} }$: $(9,12,15)$
- $\pu{\mathbf{40} \mathbf{cm} }$: $(8,15,17)$
- $\pu{\mathbf{48} \mathbf{cm} }$: $(12,16,20)$
In contrast, some lengths of wire, like $\pu{20 cm}$, cannot be bent to form an integer sided right angle triangle, and other lengths allow more than one solution to be found; for example, using $\pu{120 cm}$ it is possible to form exactly three different integer sided right angle triangles.
- $\pu{\mathbf{120} \mathbf{cm} }$: $(30,40,50)$, $(20,48,52)$, $(24,45,51)$
Given that $L$ is the length of the wire, for how many values of $L \le 1\,500\,000$ can exactly one integer sided right angle triangle be formed?