E 5/A#
The E 5 chord consists of the E (Perfect unison) and B (Perfect fifth) notes, with A# as the bass note.

How to play the E 5/A# chord
- Play A# as the lowest bass note in the left hand
- Find E (Root) on the piano keyboard
- Add B (Perfect fifth) — 7 semitones above E
- Press all 3 notes simultaneously to sound the E 5/A# chord