Agniveshyagrihyasutra 3.8.1.1

3.8.1.1

ekāhaṃ dhunupustrīṇyahāni dhunuyuḥ pañcasaptanavaikādaśārdhamāsān dhunuyuḥ ayugmarātrīrardhamāsān māsānṛtūn saṃvatsaraṃ vā saṃpādya dhunuyuriti \

They should shake for one day, they should shake for three days, they should shake for five, seven, nine, [or] eleven fortnights; having completed an uneven number of nights, fortnights, months, seasons, or a year, they should shake.