Aa permutation algorithm
PLL (permute the last layer). Group: Corners only.
Aa permutation: the top face is yellow all over. The algorithm moves the back-left corner piece to the front-right corner, and moves the front-left corner piece to the back-left corner, and moves the front-right corner piece to the front-left corner.
The diagram shows the cube from above with the front at the bottom and yellow on top.
Algorithm
R' D R U' R' D' R U' R' D R U2 R' D' R
15 moves.
Other algorithms
x R' U R' D2 R U' R' D2 R2 x'l' U R' D2 R U' R' D2 R2 x'y x' R2 D2 R' U' R D2 R' U R' x
Source: www.speedsolving.com