hp49 en hp50

[qgrdne]

Mode RPN, for the hp49 and hp50.
I used the following command:
'2^2^2^2'
The result is: 65536.
The answer should be: 256
With the hp48 (and hp85) I get the result 256.
Any idea why the HP-49 and HP-50 gives this result (65536)?

[Eduardo Duenez]

Exponentiation is evaluated right-to-left in the absence of parentheses:

2^2^2^2 = 2^(2^(2^2))