Brihat Jataka
संस्कारनाममात्रा द्विगुणा छायांगुलै: समायुक्ता: ॥ शेषं त्रिनवकभक्तान्नक्षुत्रं तद्धनिष्ठादि ॥ २६-१५ ॥
The mantras in a name from one’s naming ceremony is multiplied by two with those (added to) the digits of the shadow and joined to the remainder divided by 27, is that nakshatra beginning with Dhanishtha nakshatra.
english translation
saMskAranAmamAtrA dviguNA chAyAMgulai: samAyuktA: ॥ zeSaM trinavakabhaktAnnakSutraM taddhaniSThAdi ॥ 26-15 ॥
hk transliteration by Sanscript