Especialize is not a word. It should be replaced with ‘specialize. In the emboldened part the verb ‘underscore’ is plural while it needs to be singular to match with its subject ‘concept’. Hence, it should be ‘underscores.
What will come in place of the question mark (?) in the following series?
120, 128, 144, 168, 240
128 384 48 144 20 54
11, 1341, 3070, 5267, 8011, 11386
7, 15, 31, 79, 271, 1221
23, 45, 115, 161, 270, 349
42, 32, 60, 48, 96, 84
8, 29, 152, 1073, 9660, 106361
16, 36, 128, 768, 6144, 61440
32, 48, 72, 108, 162, 248
120, 60, 80, 90, 180, 450