I would like an example with proof or appropriate reference of a differential equation that does not admit analytic (in the sense of convergent power series, not in the sense of closed form) solutions, excepting perhaps some thin set.
I do know of a paper on a differential equation with no computable solutions, and since analytic would imply computable, this counts for the non analytic part . But, I would rather an example, or by preference a broad family of examples, in which the the solutions are computable just not analytic.