Изменения

<tex>G(z)=\frac{1/3}{(1-z)^2}+\frac{7/9}{1-z}-\frac{1/2}{1-2z}+\frac{7/18}{1-4z}=</tex>  <tex>\frac{1}{3}\sum_{n=0}^{\infty} (n+1)z^n +\frac{7}{9}\sum_{n=0}^{\infty} z^n - \frac{1}{2}\sum_{n=0}^{\infty} 2^n z^n + \frac{7}{18}\sum_{n=0}^{\infty} 4^n z^n</tex>  <tex>a_n=\frac{n+1}{3}+\frac{7}{9}-\frac{2^n}{2}+\frac{7*4^n}{18}=\frac{7*4^n+6n+20}{18}-2^{n-1}</tex>