A1 = [ 3 17 10 ; 2 4 -2 ; 6 18 -12 ]  (Golub example 3.4.1 p113)

A2 = [ 1 4 7 ; 2 5 8 ; 3 6 10 ]
b1 = [ 1 1 1 ]'                       (Golub example 3.2.8 p99)

A3 = [ 10 20 30 ; 20 45 80 ; 30 80 171 ] (Golub example 4.1.2 p139)
b2 = A3 * [ 1 ; 2 ; 3 ]

A4 = [ 1 2 4 8 ; 0 1 2 4 ; -1 0 1 2 ; -2 -1 0 1 ] (My own)

A5 = [ 1 2 ; 0 5 ; 7 -1 ] (Full rank skinny)