PauranicMantra
Om Namo Bhagavate Vasudevaya
The twelve-syllable Vishnu mantra that opens the Bhagavata Purana.
Bhagavata Purana 1.1.1Vishnu12 syllables
VedicSukta (hymn)
Purusha Sukta — opening verse
The thousand-headed Purusha — the first verse of the Purusha Sukta, Rigveda 10.90.1.
Rigveda 10.90.1Vishnu