Śukadeva Gosvāmī said: Thereafter, when his son Sudyumna had thus gone to the forest to accept the order of vānaprastha, Vaivasvata Manu [Śrāddhadeva], being desirous of getting more sons, performed severe austerities on the bank of the Yamunā for one hundred years.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
श्रीशुक उवाच । एवं गतेऽथ सुद्युम्ने मनुर्वैवस्वतः सुते । पुत्रकामस्तपस्तेपे यमुनायां शतं समाः
śrīśuka uvāca | evaṃ gate'tha sudyumne manurvaivasvataḥ sute | putrakāmastapastepe yamunāyāṃ śataṃ samāḥ
SB 9.2.1