Number of atoms in nanotube.

Changed in version 0.3.0: Returns total number of atoms per nanotube. Use Natoms_per_unit_cell to get the number of atoms per unit cell.

\[N_{\mathrm{atoms}} = 2N\times n_z = \frac{4(n^2 + m^2 + nm)}{d_R}\times n_z\]

where \(N\) is the number of graphene hexagons mapped to the nanotube unit cell and \(n_z\) is the number of unit cells.