Nominative: ـَانِ — طَالِبَانِ. The alif is the case marker.
Accusative: ـَيْنِ — طَالِبَيْنِ. The yāʾ is the case marker.
Genitive: ـَيْنِ — طَالِبَيْنِ. The yāʾ is the case marker.
The accusative and genitive have the same form, but different grammatical governors may require them.