Huṁhuṅkasutta
Evaṁ me sutaṁ— ekaṁ samayaṁ bhagavā uruvelāyaṁ viharati najjā nerañjarāya tīre ajapālanigrodhe paṭhamābhisambuddho. Tena kho pana samayena bhagavā sattāhaṁ ekapallaṅkena nisinno hoti vimuttisukhapaṭisaṁvedī. Atha kho bhagavā tassa sattāhassa accayena tamhā samādhimhā vuṭṭhāsi.
The Mystic Syllable Huṁ
So I have heard. At one time, when he was first awakened, the Buddha was staying in Uruvelā at the goatherd’s banyan tree on the bank of the Nerañjarā River. There the Buddha sat cross-legged for seven days without moving, experiencing the bliss of freedom. When seven days had passed, the Buddha emerged from that state of immersion.