We shouldn't exaggerate.

The Unicode database is necessary for case conversion (uc/lc) and regex matches (is something a whitespace? or a letter? or a number?). Whereas the OEIS database would be only useful for one operator, and even there it's only part of the solution - if you know that a sequence represents a part of the prime numbers, you still have no really efficient way of generating them lazily.

However a library could easily override the infix:<...> operator and thus do what you want.