Garudapurana 1.39.5

1.39.5

oṃ arkāsanāya namaḥ /
oṃ hrāṃ sūryamūrtaye namaḥ /
etāstu pūjayenmadhye hranmantrāñchṛṇu śaṅkara /
oṃ haṃ saṃ khaṃ khakholkāya krāṃ krīṃ saḥ svāhā sūryamūrtaye namaḥ /
anenāvāhanaṃ kuryātsthāpanaṃ sannidhāpanam /
sanniropanamantreṇa sakalīkaraṇaṃ tathā //

"Om, homage to the seat of the Sun.
Om hrāṃ, homage to the embodiment of the Sun."
One should worship these in the center. Listen to the mantras of the heart, O Śaṅkara:
"Om haṃ saṃ khaṃ khakholkāya krāṃ krīṃ saḥ svāhā, homage to the embodiment of the Sun."
With this one should perform the invocation, the installation, the bringing near,
the confrontation with its mantra, and likewise the endowment with parts.