# Do even modes exist for e.g. pipes closed at one end?

This is really a question about terminology, The wavelength of a standing wave in a e.g. pipe closed at one end and open at the other is said to be $$\frac{4L}{n}$$, where $$L$$ is its length and $$n$$ is an odd natural number. Is it correct to say that the second mode of this pipe has wavelength $$\frac{4L}{3}$$ and the fourth has wavelength $$\frac{4L}{7}$$ etc, or is it correct to say that $$\frac{4L}{3}$$ and $$\frac{4L}{7}$$ are the wavelengths for the third and seventh mode (i.e. the nth mode) and the second and fourth modes etc don’t exist for this pipe?