The A augmented seventh chord is a 4-note chord consisting of the notes A, C#, E# and G#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as Amaj7#5.
Chords that are a subset of Amaj7#5. These contain less notes but all of them are included in Amaj7#5.
In case you prefer a non-interactive variant of the chord chart, we've embedded a PNG image below that shows the notes for the the Amaj7#5 chord. Feel free to save or share the image as needed.