P. 182, line 14

The equation should be

$\frac{d^{2}y}{d{x}^2}=\sum _{n=2}^{\mathrm{\infty }}n(n-1)a_n{x}^{n-2}=\sum _{n=0}^{\mathrm{\infty }}(n+2)(n+1)a_{n+2}{x}^n$

Return to errata.