  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 several
$\mathrm{nb}$ and we would expect several tens 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. Our study can also tell where to search for the
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. 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 $P_c(4457)$.
