A Phrygian scale
The A Phrygian scale has the formula 1, b2, b3, 4, 5, b6, b7 with notes A, A#, C, D, E, F, G
The Phrygian scale is the third of the seven modes. It is similar to the natural minor scale, but with flat 2nd note. This scale is often used in Latin, Spanish, and flamenco music.