We propose an axiomatic foundation of mathematics based on the finite sequence as the foundational concept, rather than based on logic and set, as in set theory, or based on type as in dependent type theories. Finite sequences lead to a concept of pure data, which is used to represent all mathematical objects. As an axiomatic system, the foundation has only one axiom which defines what constitutes a valid definition. Using the axiom, an internal true/false/undecided valued logic and an internal language are defined, making logic and language-related axioms unnecessary. Valid proof and valid computation are defined in terms of equality of pure data. An algebra of pure data leads to a rich theory of spaces and morphisms which play a role similar to the role of Category Theory in modern Mathematics. As applications, we explore Mathematical Machine Learning, the consistency of Mathematics and address paradoxes due to Godel, Berry, Curry and Yablo.