Recursive variadic template specialization

My target is to define a Recursive class, templated on an int N and one or more types T, ...Ts, which should behave like a std::pair with

• a std::array of N items of type T as the first,
• and, as second, an optional std::vector of Recursive instances templated on the same N and on the remaining template arguments Ts....

In trying to write down the class given the above requirements, I've come up with this non-working code (where I've also defined some necessary, as they help a lot, aliases for two instantiations of Recursive), and I don't know if I have mis-designed what I described above (or if it is an ill-formed description!), or if I'm misusing the language syntax.

#include <array>
#include <boost/hana/fwd/optional.hpp>
#include <boost/hana/optional.hpp>
#include <string>
#include <utility>
#include <vector>

template <int N, typename T1, typename T2, typename ...Ts>
struct Recursive : std::pair<std::array<T1, N>,
                             boost::hana::optional<std::vector<Recursive<N, T2, Ts...>>>
                            > {};

template <int N, typename T>
struct Recursive<N, T> : std::array<T, N> {};

template<typename ...T>
using Recursive2 = Recursive<2u, T...>;

template<typename ...T>
using Recursive3 = Recursive<3u, T...>;

int main() {
    Recursive2<int> x(std::make_pair(std::array<int, 2>{0,0}, boost::hana::nothing));
}