[tex]7 = {2}^{1} + {2}^{0} + {2}^{2} [/tex]
[tex]31 = {2}^{4} + {2}^{0} + {2}^{2} [/tex]
[tex]90 = {3}^{4} + {3}^{2} [/tex]
[tex]121 = {3}^{4} + {3}^{3} + {3}^{2} + {3}^{0} + {3}^{1} [/tex]
[tex]129 = {2}^{7} + {2}^{1} \\ 129 = {5}^{3} + {5}^{2} + {5}^{2} + {5}^{0} + {5}^{0} + {5}^{0} + {5}^{0} [/tex]
