w = triang(L)
See Definitions for the equations that define the triangular window. The triangular window is very similar to a Bartlett window. The Bartlett window always ends with zeros at samples 1 and L, while the triangular window is nonzero at those points. For L odd, the center L-2 points of triang(L-2) are equivalent to bartlett(L).
 Oppenheim, Alan V., Ronald W. Schafer, and John R. Buck. Discrete-Time Signal Processing. Upper Saddle River, NJ: Prentice Hall, 1999.