Shiva Purana
ॐमाद्यैः पंचभिर्ब्रह्ममंत्रैस्सद्यादिभिः क्र्मात् ॥ सुगंधकुसुमैर्माल्यैरलंकुर्य्याद्रथं च तम् ॥ ४८ ॥
The chariot shall be decorated with fragrant flowers and garlands with the five Brahma mantras beginning with Sadyojāta preceded by Om.
english translation
OMmAdyaiH paMcabhirbrahmamaMtraissadyAdibhiH krmAt ॥ sugaMdhakusumairmAlyairalaMkuryyAdrathaM ca tam ॥ 48 ॥
hk transliteration by Sanscript