4. Using 1 cent, 2 cent, and 5 cent coins to make up one yuan, how many different ways are there?

将上面的文本翻译成英文，请保留源文本的换行和格式，直接输出翻译结果。 

Note: The last sentence is a repetition of the instruction and should not be included in the translation. Here is the final version:

4. Using 1 cent, 2 cent, and 5 cent coins to make up one yuan, how many different ways are there?
4.【Solution】All are 5-cent coins, 20 of which can make up one dollar. Taking out 1 5-cent coin and exchanging it for 1-cent and 2-cent coins, there are 3 ways (2 2-cent coins, 1 2-cent coin, and 0 2-cent coins); taking out 2 5-cent coins and exchanging them for 1-cent and 2-cent coins, there are 6 ways; taking out 3 5-cent coins and exchanging them for 1-cent and 2-cent coins, there are 8 ways. And so on, when taking out an odd number of 5-cent coins $n$, the number of ways is $(n \times 5 + 1) \div 2$, and when taking out an even number of 5-cent coins $n$, the number of ways is $n \times 5 \div 2 + 1$. Therefore, using 1-cent, 2-cent, and 5-cent coins to make up one dollar, there are
$$
\begin{array}{l}
1+((1+3+5+\cdots+19) \times 5+10) \div 2+(2+4+6+\cdots+20) \times 5 \div 2 \\
+10=541
\end{array}
$$

different ways.