Jaiminīya (Talavakāra) Brāhmaṇa 2-7.238

Now, for whomsoever the first day of this [two-day rite] is a Jyotir-ukthya and the second is an Āyur-atirātra: with this King Abhipratārin indeed sacrificed, desiring offspring and wishing to outdo Khalatī Daivovāta. Thereupon he indeed cut off Khalatī Daivovāta. He obtained this much offspring. Three [verses] of the one [day] are left over, [and] the other is deficient by two. Those three [verses] that are redundant belong to the male, by which he procreates. Those two [verses] that are deficient belong to the female, from which she brings forth. Thus this productive pairing is made. He who knows this is born through a productive pairing. Both those [sets of] stoma verses amount to seven hundred and twenty-one. That many are the days and nights of the year. The year, verily, is the complete Prajāpati, [so they thought,] 'May we succeed in reaching the complete Prajāpati; may the complete Prajāpati come to us.' Now, the one stoma verse that is left over is indeed the world of the sacrificer. A Brahmin repeatedly said to him: 'No further hero like this will be born in his offspring; he made a world for himself alone, not for offspring, for he attained only this one world.'

Recognizing that, he said: 'Let it be according to the divine will for his offspring!'

'A god among gods, I have cut off Khalatī Daivovāta!'

Then both of them grieved for him in that way; they burned [with sorrow] for him in that way.

That very thing is this.

These descendants of Abhipratārin are only this many; no further such hero is born among them.

Now, of this [rite], alternating with the trivṛt and pañcadaśa [stomas]:

the first day is an Agniṣṭoma,

[and] the second is an all-stoma Atirātra.

One desiring procreation should sacrifice with this.

The trivṛt and pañcadaśa stomas are deficient and redundant, a productive pair.

One is deficient, the other is redundant.