Problem with a list in CAS-program

[webmasterpdx]

The HP Prime wiki has a CAS vs HOME article linked to from the Programming Documentation section and in there it says:

Indexing in HP Basic is done using () braces, as in L1(5). In CAS, () can be used with a constant index in read only mode, but when a variable index is used, due to parsing issues (it thinks L1(x) is a function call), you must use [] braces instead, as in L1[i]. So, it is recommended if in CAS mode or in a CAS program, it is best to use [] to index always. This applies to Lists, Matrices and Vectors (1D Matrix). In XCas, lists, matrices and vectors are all lists. Note that XCas uses [] always anyway, so this keeps the Prime's CAS compatible with XCas.

http://www.wiki4hp.com/doku.php?id=prime:start