Why Does n_0(x) Fail to Satisfy the Spherical Bessel Equation?

[Logarythmic]

What am I missing when I'm unsuccessful in showing by direct substitution into the spherical Bessel equation

$$r^2 \frac{d^2R}{dr^2} + 2r \frac{dR}{dr} + [k^2 r^2 - n(n + 1)] R = 0$$

that

$$n_0 (x) = - \frac{1}{x} \sum_{s \geq 0} \frac{(-1)^s}{(2s)!} x^{2s}$$

is a solution?

What's the catch??

 

[Logarythmic]

Ok, if there is no catch, can someone give me at starter here?