Turing's paper is a landmark, and includes even an equivalence proof of the power of the lambda calculus and his universal machine. In doing so, he came up with a fixed-point combinator, an applicative combinator, now called the Turing fixed point combinator [1]. Especially appropriate on a website run by the Y combinator.
Turing's paper should run as a TV ad "But wait, there's more..." Many applications of topology (he argues why the alphabet should be finite, rather than simply saying that it is finite, by using the Bolzano-Weierstrass theorem, essentially), combinatorics, logic, functional programming - when FP was hardly a decade old and largely unknown outside Princeton - and all from an undergraduate course project report!
[1] https://en.wikipedia.org/wiki/Fixed-point_combinator#Other_f...