HP 38G: Better than Prime for some Sequences using the built in Sequence App

[Tim Wessman]

(03-07-2015 05:29 AM)BruceH Wrote:  It's to do with the use of U1 as the index to U1. I tried setting U2 to be U1(N-1) and making the appropriate substitution and that still fails. Creating a user defined function TT(N)=U1(N-1) and substituting also fails. So I think the Sequence app is scanning the parse tree in an effort to avoid a recursive loop and is rejecting cases that would actually work.

Something like this is indeed the issue. The other is that the application was originally implemented by individuals who had basically never touched a calculator (of any type) in their lives. Having something that didn't match exactly U<#>(N),U<#>(N-1), or U<#>(N-2) on parse time meant that it would be blocked.

Anyway, I would appreciate if anyone interested can provide more sequences or tests you'd like me to get into our test plans.

The one that started this thread has been added ( TEVAL(U1(99)) --> .056_s), but I'd appreciate more from interested parties. Honestly, the sequence application hasn't been touched primarily because we've had basically zero feedback from anyone on it (apart from this and the "start at 0" complaint). Most educators don't tend to teach sequences in many places. Most users never touch it either. :-|

I know before I started working for HP I'd never really once touched sequences in earlier calculators or any classes.