GLYPH<s48> GLYPH<s49>GLYPH<s48>GLYPH<s48> GLYPH<s50>GLYPH<s48>GLYPH<s48> GLYPH<s51>GLYPH<s48>GLYPH<s48> GLYPH<s45>GLYPH<s49>GLYPH<s46>GLYPH<s48> GLYPH<s45>GLYPH<s48>GLYPH<s46>GLYPH<s53> GLYPH<s48>GLYPH<s46>GLYPH<s48> GLYPH<s45>GLYPH<s48>GLYPH<s46>GLYPH<s52> GLYPH<s45>GLYPH<s48>GLYPH<s46>GLYPH<s50> GLYPH<s48>GLYPH<s46>GLYPH<s48> GLYPH<s48>GLYPH<s46>GLYPH<s50> GLYPH<s48>GLYPH<s46>GLYPH<s52> GLYPH<s45>GLYPH<s48>GLYPH<s46>GLYPH<s49> GLYPH<s48>GLYPH<s46>GLYPH<s48> GLYPH<s48>GLYPH<s46>GLYPH<s49> GLYPH<s48>GLYPH<s46>GLYPH<s50> GLYPH<s48>GLYPH<s46>GLYPH<s57>GLYPH<s57>GLYPH<s53> GLYPH<s49>GLYPH<s46>GLYPH<s48>GLYPH<s48>GLYPH<s48> GLYPH<s32> GLYPH<s32>GLYPH<s98> GLYPH<s50> GLYPH<s32>GLYPH<s98> GLYPH<s51> GLYPH<s32>GLYPH<s98> GLYPH<s52> GLYPH<s32>GLYPH<s98> GLYPH<s54> GLYPH<s98> GLYPH<s107> GLYPH<s65> GLYPH<s40>GLYPH<s98>GLYPH<s41> GLYPH<s32> GLYPH<s32> GLYPH<s69>GLYPH<s32>GLYPH<s47>GLYPH<s32>GLYPH<s69> GLYPH<s48> GLYPH<s50> GLYPH<s40> GLYPH<s97> GLYPH<s41> GLYPH<s50>GLYPH<s48>GLYPH<s56> GLYPH<s80>GLYPH<s98> FIG. 2: (Color online) (a) Energy of $^{208}$Pb with respect to β$_{2}$ and β$_{4}$ deformation with Skyrme energy density functional approach. (b) The value of b$_{k}$ as a function of mass number. The scattered symbols denote the obtained curvatures of the parabolas with the Skyrme force SkM* for a number of nuclei. The solid curves denote the corresponding results with an empirical formula (6). see that the parabola approximation to the change of energy with β$_{2}$ is acceptable. Fig.1(b) shows the value of b$_{2}$ as a function of the mass number. The crosses denote the results of the SkM* interaction for a number of nuclei along the β -stability line. We find that the dependence of b$_{2}$ on the mass number A can be reasonably well described by a formula This form of mass dependence of b$_{2}$ is therefore adopted in the proposed mass formula and the optimal values of g$_{1}$ and g$_{2}$ are finally determined by the 2149 measured nuclear masses [6]. b$_{2}$ = g$_{1}$A 1 / 3 + g$_{2}$A − 1 / $^{3}$. (5) 6