Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 2
ततोऽयजन्मनुर्देवमपत्यार्थं हरिं प्रभुम् ।इक्ष्वाकुपूर्वजान् पुत्रान्लेभे स्वसदृशान् दश ॥ २ ॥
tato ’yajan manur devamapatyārthaṁ hariṁ prabhumikṣvāku-pūrvajān putrānlebhe sva-sadṛśān daśa
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.