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Ramanujan's Square Equation

It has been proved that the only solutions to the Diophantine Equation

\begin{displaymath}
2^n-7=x^2
\end{displaymath}

are $n=3$, 4, 5, 7, and 15 (Beeler et al. 1972, Item 31).


References

Beeler, M.; Gosper, R. W.; and Schroeppel, R. HAKMEM. Cambridge, MA: MIT Artificial Intelligence Laboratory, Memo AIM-239, Feb. 1972.




© 1996-9 Eric W. Weisstein
1999-05-25