5777
This number is a composite.
In 1752, Goldbach conjectured in a letter to Euler that every odd integer can be
written in the form p + 2a2, where p is unity or a prime and a is allowed to be zero. This is not the conjecture Goldbach is famous for because it is false--in 1856, M. A. Stern and his students found the only two known exceptions, 5777 being the smallest. Can you find the other?
(There is one curio for this number that has not yet been approved by an editor.)
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