A036236

[Richard Guy]

Ron Graham, to whom I'm copying this, can give you the
date.  He was interested in the problem (at least 30
years ago?) and Dick Lehmer did a search for him.  I
got it from Lehmer -- it wasn't published, except in
UPINT, which is why my name has got connected to it.

R.

On Tue, 13 Aug 2002, David Wilson wrote:

> Regarding the congruence 2^n == 3 (mod n).
> 
> A036236 attributes the solution n = 4700063497 to Lehmer, while
> http://mathworld.wolfram.com/2.html credits Guy.  I think Lehmer is
> correct, but I don't know the date.  Also, Eric's page misses the
> trivial solution n = 1.
> 
> 
>