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I was thinking about an elementary question

For some given $k\in \mathbb N$, find $k$ consecutive composite integers.

The answer that is generally expected is

The following $k$ integers are consecutive and composite $$(k+1)!+2\\(k+1)!+3\\(k+1)!+4\\.\\.\\.\\(k+1)!+(k+1)$$

While this is a perfectly fine answer, I was thinking about how big these numbers will get even for very small values of $k$. For example, the first three consecutive numbers (found by trial and error) are $$8,9,10$$ and the first four consecutive composite numbers are $$24,25,26,27$$ but the sets we obtain through taking factorials are $26,27,28$ and $122,123,124,125$ respectively. So I was thinking of trying to make these numbers smaller.

One way I thought was to use the $\operatorname{L.C.M.}$ of these numbers instead, i.e., saying

The following $k$ integers are consecutive and composite $$\operatorname{L.C.M.}\{1,2,\dots ,k+1\}+2\\\operatorname{L.C.M.}\{1,2,\dots ,k+1\}+3\\\operatorname{L.C.M.}\{1,2,\dots ,k+1\}+4\\.\\.\\.\\\operatorname{L.C.M.}\{1,2,\dots ,k+1\}+(k+1)$$

While this bound gives us the correct answer for finding the first three consecutive composite integers, for four, it generates the set $62,63,64,65$. It is quite clear that even this one will shoot farther away from the first few numbers with increasing $k$.

So, the question is, is it possible to point out exactly the first few composite numbers? If not, then how close can we get to it?

Sayan Dutta
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    Interesting question. The guess of a layman: this would not be possible any more than it is possible to predict what the next prime number after a certain prime is. – Snaw Dec 12 '21 at 11:08
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    The first three consecutive numbers are $8,9,10$, and the first four consecutive composite numbers are $24,25,26,27$. – mathlove Dec 12 '21 at 11:24
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    Read the wikipedia article about prime gaps to see that the gaps occur far earlier than the bound we get with the lcm-construction. This is just a construction showing that the magnitude of the prime gaps is not bounded. For the sake of simplicity , usually the factorials are used. A construction with even smaller numbers can be achieved using the primorials. – Peter Dec 12 '21 at 13:07
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    Maybe, you are also interest in the so-called "merit" , a measure of the magnitude of the prime gap. Dana Jacobsen holds almost all records having to do with finding prime gaps with extreme magnitudes. Surprisingly, the merit is also unbounded although the largest known merit is still relatively small. – Peter Dec 12 '21 at 13:13
  • @SathvikAcharya yes, thanks! – Sayan Dutta Dec 13 '21 at 07:05
  • @Peter thanks! Your comments were very useful! – Sayan Dutta Dec 13 '21 at 07:06

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