Brihajjataka 7.7

7.7

āyur dāyaṃ viṣṇu gupto api ca evaṃ deva svāmī siddhasenaś ca cakre/
doṣaś ca eṣāṃ jāyate aṣṭāv ariṣṭaṃ hitvā na āyur viṃśateḥ syād adhastāt//(śālinī)

Viṣṇugupta also calculated the longevity thus, and so did Devasvāmin and Siddhasena;
and a defect arises in their [systems]: having set aside infant mortality, longevity would never be below twenty [years].