Valmiki Ramayana Ayodhya Kanda Sarga 8 Shloka 22
Original Shlokaभविता राघवो राजा राघवस्यानु यस्सुतः। राजवंशात्तु कैकेयि भरतःपरिहास्यते।।2.8.22।।
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राघव: the scion of the Raghus (Rama), राजा as king, भविता will become, राघवस्य अनु suceeding Rama, य: who, सुत: (his) son( will become king), कैकेयि O Kaikeyi, भरत: तु on the contrary Bharata, राजवंशात् from royal dynasty, परिहास्यते will be debarred.
Rama, the scion of the Raghus, will become king. After Rama, his son will suceed him. O Kaikeyi, as for Bharata, he will be debarred from royal succession (altogether).