  We present a study on ab-initio calculations of three-neutron correlators
from Lattice QCD. We extend the method of baryon blocks to systems of three
spacially displaced baryons. This allows the measurement of three-neutron
$p$-wave correlators with total spin $S=1/2$ and $3/2$. In addition, we use
automatic code generation that has high flexibility and allows for easy
inclusion of additional channels in the future while optimizing the evaluation
of contractions. Our measurements were performed on a newly generated $96\times
48^3$ Clover-Wilson gauge field ensemble with $m_{\pi} \approx
370\,\text{MeV}$. We present preliminary results of our calculations of one
pion and nucleon as well as two nucleon ($2N$) and three neutron ($3n$)
correlators.
