T(N) = 2^k - 1 + 2^k * T(N / 2^k)
     = 2^(log N) - 1 + 2^(log N) * T(N / 2^log(N))
     = N - 1 + N * T(N/N)
     = N - 1 + N * 1
     = 2*N - 1