What is the N_PRB of LTE stands for in Table 7.1.7.2.1.1-1 of 3GPP TS 36.213 V14.17.0?

In Table 7.1.7.2.1.1-1 of 3GPP TS 36.213 V14.17.0, we can find the packet size by I_TBS and N_PRB. Or if we know the packet size (e.g. 350 KB), we can find the N_PRB which is needed to carry the packet.

As the packet is transmitted in 1 subframe, what is the exactly number of RBs is needed after we got the N_PRB? For example, if we got N_PRB = 13 from the table, does it need 13 * 2 = 26 RBs in the subframe (13 RBs in each slot) or need 13 RBs in the subframe (7 RBs in each slot)?

13 RBs in each slot