Liouville's constant is an artificially-constructed mathematical constant defined as:


Liouville's constant can be constructed in base $b$ by replacing the $10^{-n!}$ with $b^{-n!}$.

Now let's consider the sum that produces Liouville's Constant in base $b$: $\displaystyle\sum_{n\in\mathbb{Z}^{+}}b^{-n!}$

And finally, the question I was getting at. Is the following integral:


convergent or divergent?

I honestly don't even know where to start. How would I go about estimating the value of this integral if it converges?


1 Answer 1


First interchange the order of the integration and the summation to get $$\sum_1^\infty\int_0^1 x^{n!}dx=\sum_1^\infty\frac{1}{n!+1}$$ Now, $$n!\lt n!+1$$ so $$\frac{1}{n!+1}\lt\frac{1}{n!}$$ this gives $$\sum_1^\infty\frac{1}{n!+1}\lt\sum_1^\infty\frac{1}{n!}=e-1$$ by the series definition of e, thus the series converges.

  • 1
    $\begingroup$ Nice! Answer! Very concise $\endgroup$
    – jonan
    Commented Nov 24, 2019 at 16:08

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