Nuttall-defined minimum 4-term Blackman-Harris window
w = nuttallwin(N)
w = nuttalwin(N,SFLAG)
w = nuttallwin(N) returns a Nuttall defined N-point, 4-term symmetric Blackman-Harris window in the column vector w. The window is minimum in the sense that its maximum sidelobes are minimized. The coefficients for this window differ from the Blackman-Harris window coefficients computed with blackmanharris and produce slightly lower sidelobes.
w = nuttalwin(N,SFLAG) uses SFLAG window sampling. SFLAG can be 'symmetric' or 'periodic'. The default is 'symmetric'. You can find the equations defining the symmetric and periodic windows in Definitions.
The equation for the symmetric Nuttall defined 4-term Blackman-Harris window is
where n= 0,1,2, ... N-1.
The equation for the periodic Nuttall defined 4-term Blackman-Harris window is
where n= 0,1,2, ... N-1. The periodic window is N-periodic.
The coefficients for this window are
a0 = 0.3635819
a1 = 0.4891775
a2 = 0.1365995
a3 = .0106411
 Nuttall, Albert H. "Some Windows with Very Good Sidelobe Behavior." IEEE® Transactions on Acoustics, Speech, and Signal Processing. Vol. ASSP-29, February 1981, pp. 84–91.