Then, because of this desire for sons, the Manu known as Śrāddhadeva worshiped the Supreme Lord, the Personality of Godhead, the Lord of the demigods. Thus he got ten sons exactly like himself. Among them all, Ikṣvāku was the eldest.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
ततोऽयजन्मनुर्देवमपत्यार्थं हरिं प्रभुम् । इक्ष्वाकुपूर्वजान् पुत्रान् लेभे स्वसदृशान् दश
tato'yajanmanurdevamapatyārthaṃ hariṃ prabhum | ikṣvākupūrvajān putrān lebhe svasadṛśān daśa
SB 9.2.2