  Using the level truncation method, we construct numerical solutions, which
are twist even and SU(1,1) singlet, in the theory around the Takahashi-Tanimoto
identity-based solution (TT solution) with a real parameter $a$ in the
framework of bosonic open string field theory. We find solutions corresponding
to "double brane" and "ghost brane" solutions which were constructed by Kudrna
and Schnabl in the conventional theory around the perturbative vacuum. Our
solutions show somewhat similar $a$-dependence to tachyon vacuum and single
brane solutions, which we found in the earlier works. In this sense, we might
be able to expect that they are consistent with the conventional interpretation
of $a$-dependence of the TT solution. We observe that numerical complex
solutions at low levels become real ones at higher levels for some region of
the parameter $a$. However, these real solutions do not so improve
interpretation for double brane.
