Simple n-dimensional array class ( Tensor ) in C++

Tensor.h

#ifndef TENSOR_H
#define TENSOR_H

#include <vector>
#include <ostream>

static bool math_indexing = true;

template<typename T, size_t size>
class Tensor {
public:
    template<typename ...Args>
    Tensor(size_t first, Args&&... args){
        data = std::vector<Tensor<T, size-1> >(first, Tensor<T, size-1>(args...));
    }
    Tensor<T, size-1> operator[](size_t idx){ return data[idx - math_indexing]; }
    friend std::ostream& operator<<(std::ostream& out, const Tensor& t){
        out << "[ ";
        for(Tensor<T, size-1> tensor : t.data)
            out << tensor << ", ";
        out << "]";
        return out;
    } 
private:
    std::vector<Tensor<T, size-1> > data;
};

template<typename T>
class Tensor<T, 1> {
public:
    Tensor(size_t size) : data(size) {}
    T operator[](size_t idx){ return data[idx - math_indexing]; }
    friend std::ostream& operator<<(std::ostream& out, const Tensor<T, 1>& t){
        out << "[ ";
        for(T val : t.data)
            out << val << ", ";
        out << "]";
        return out;
    }
private:
    std::vector<T> data;
};

#endif