14. Starting from the number 3, repeat the operations of multiplying by 2 and subtracting 1, 30 times, the result obtained is ( ).
(A) $3 \times 2^{30}$
(B) $3 \times 2^{31}$
(C) $2^{31}+1$
(D) $2^{31}-1$
(E) None of the above answers are correct
14. (C) From the problem, we have $3 \cdot 2^{30}-2^{29}-2^{28}-\cdots-2-1$ $=3 \cdot 2^{30}-\left(2^{30}-1\right)=2^{31}+1$.