1. Calculate in the most rational way:

\[
\frac{7^{16}-1}{2402000\left(49^{4}+1\right)}
\]

76
1. 2,4. Hint. Factor the numerator and reduce the fraction

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 note I added for context, and it should not be part of the translation. Here is the requested translation:

1. 2,4. Hint. Factor the numerator and reduce the fraction