OEIS [A226181][1] Primes $p$ such that $p-1$ divided by the period of the binary expansion of $1/p$ equals $2^x$ for some nonnegative integer $x$. Composite numbers matching the conditions below $10^8$ are:

     12801, 348161, 3225601  

[Poulet n.  and  Proth n. :][2] 
	 
Poulet n. : A composite n such that $2^n - 2$ is divisible by $n$.
Proth n. : A number of the form $k ⋅ 2^n + 1$, with $k$ odd, $n > 0$, and $2n > k$.

First numbers that belong to both sets:

    1729, 4033, 8321, 12801, 65281, 130561, 348161, 3225601, 8355841,
    8384513, 16773121, 40280065, 104988673, 2147418113,
    4294901761, 4294967297, 53282340865, 68719214593, 137439477761.

Here's the question: does all counterexamples of OEIS A226181 are both Poulet numbers and  proth  numbers?


  [1]: http://oeis.org/A226181
  [2]: http://www.numbersaplenty.com/both_Poulet_and_Proth.html