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arXiv · 2004.09256

Results of Brocard-Ramanujan problem on diophantine equation $n!+1=m^2$

Somnath Maiti
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Abstract

The Brocard-Ramanujan problem pertaining to the diophantine equation $n!+1=m^2$, a famously unsolved problem, deals with finding the integer solutions to the equation. Nobody has discovered any new solution of the problem beyond $n=4,~5$ and $7$ although many of us have tried it. Bruce Berndt and William Galway \cite{Berndt} had not found any new solution in 2000 by extensive computer search for a solution with $n$ up to $10^9$. The purpose of this study is to show that the solutions should satisfy some necessary and/or sufficient conditions. If $\sqrt{n!}=k+\epsilon,~n>1,~0<\epsilon<1$; then it has solution if and only if $n!=k(k+2)$ and $\epsilon,~k$ are strictly monotonic increasing. It has only finitely many solutions which is not based on any conjecture or previous research on the Brocard-Ramanujan problem. For the new solution of Brocard-Ramanujan problem ($n\ge 10^5$), the value of $\epsilon$ should be more than $0.999 \cdots 905915$ (digit 0 is coming after 228287 numbers of 9 digit, which takes more than 66 pages in (LibreOffice Writer) indicating almost impossibility of new solution. If we consider $n\geq 10^9$, I am unable to calculate the said numbers of 9 digit in the value of $\epsilon$ in my personal laptop (with 8GB Ram) using MATHEMATICA 8. Finally, it has been claimed to discover that the problem has no further solution.

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Somnath Maiti. 2020-04-09. Results of Brocard-Ramanujan problem on diophantine equation $n!+1=m^2$. https://arxiv.org/abs/2004.09256

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