Calling lambda after variadic templates

#include <iostream>
#include <tuple>

template <int... Is>
struct seq
{
};

template <int N, int... Is>
struct gens : gens<N - 1, N - 1, Is...>
{
};

template <int... Is>
struct gens<0, Is...> : seq<Is...>
{
};

template <int N, typename ... Args, int... S>
void _foo(const std::tuple<Args...>& t, seq<S...>)
{
    auto&& f = std::get<N>(t);
    f(std::get<S>(t)...);
}

template <typename ... Args>
void foo(Args&& ... args)
{
    _foo<sizeof...(Args)-1>(std::make_tuple(std::forward<Args>(args)...), gens<sizeof...(Args)-1>{});
}

int main()
{
    foo(1, 2, 3, [](auto a, auto b, auto c)
    {
        std::cout << "a= " << a << std::endl;
        std::cout << "b= " << b << std::endl;
        std::cout << "c= " << c << std::endl;
    });
    return 0;
}