  Motivated by the observation of the first hidden charm pentaquarks by the
LHCb collaboration in 2015 and the updated analysis with an order-of-magnitude
larger data set in 2019, we estimate their cross sections for the prompt
production as well as their heavy quark spin partners, in the
$\Sigma_c^{(*)}\bar{D}^{(*)}$ hadronic molecular picture, at the center-of-mass
energy $7~\mathrm{TeV}$ in the $pp$ collision. Their cross sections are tens
$\mathrm{nb}$ and we would expect several thousands hidden charm pentaquark
events in the LHC based on its current integrated luminosity. The cross
sections show a sizable deviation of the cross sections for hidden charm
pentaquarks with the third isospin component $I_z=+\frac{1}{2}$ ($P_c^+$) from
those with $I_z=-\frac{1}{2}$ ($P_c^0$). The cross sections decrease
dramatically with the increasing transverse momentum, which indicates that the
production dynamics is the non-perturbative strong interaction. Our study can
also tell where to search for the %$P_c(4380)$ and the other missing hidden
charm pentaquarks. The confirmation of the complete hidden charm pentaquarks in
the heavy quark symmetry would further verify their
$\Sigma_c^{(*)}\bar{D}^{(*)}$ molecular interpretation and exclude other
potential explanations, such as the triangle singularity interpretations and
compact pentaquarks. In addition, the relative strength among these cross
sections for pentaquarks can help us to identify the quantum numbers of the
$P_c(4440)$ and $P_c(4457)$.
