HP 9g - Graphing Calculator User Manual page 76

When the message " 1: A(N), 2 :S(N) " appears on the display, you can
input a " P " value to specify the type of operation to be
performed:
1 for A(N)
32 (1) A = 3 , D = 2, N = 4
[ ] ( 5 Seconds )
1 [ ] 3 [
2 [ ] 4
[ ]
RUN
A(N) = A (4) = 9
]
E-76
2 for S(N)