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+--- Thread: HP-80 Unexplained Key Sequence? (/thread-1680.html)
HP-80 Unexplained Key Sequence? - Max Stone - 06-21-2014 07:37 PM
Can anyone tell me why the HP-80 gives this unusual, unexplained sequence when you keep pressing Shift then the Decimal Point, giving you the following sequence (from an empty stack):
0.
1.
2.
3.
5.
11.
26.
66.
227.
1064.
6257.
62979.
1251797.
41590664.
4048283972.
Kind regards, MAX
RE: HP-80 Unexplained Key Sequence? - Massimo Gnerucci - 06-21-2014 08:11 PM
(06-21-2014 07:37 PM)Max Stone Wrote: Can anyone tell me why the HP-80 gives this unusual, unexplained sequence when you keep pressing Shift then the Decimal Point, giving you the following sequence (from an empty stack):
0.
1.
2.
3.
5.
11.
26.
66.
227.
1064.
6257.
62979.
1251797.
41590664.
4048283972.
Kind regards, MAX
We've already been here... :)
RE: HP-80 Unexplained Key Sequence? - Max Stone - 06-21-2014 08:15 PM
Thanks, interesting...one of those unexplained features of these early HP calculators.
Kind regards, MAX
RE: HP-80 Unexplained Key Sequence? - Martin Paech - 06-21-2014 08:26 PM
Unfortunately, with respect to the HP-80 I can't help, but this sequence (apparently) of integers might be of general interest (it's not in the OEIS).
RE: HP-80 Unexplained Key Sequence? - Martin Paech - 06-21-2014 08:35 PM
Thank you for the link, Massimo! Gerson W. Barbosa has also checked the OEIS in 2012: How about to publish this curious sequence?
Martin
Edit: Till now HP is only mentioned in two sequences…
RE: HP-80 Unexplained Key Sequence? - bshoring - 06-22-2014 04:40 AM
Max, does this also change the display on yours to zero places? On my HP-80 iOS emulator it does.
Bob
RE: HP-80 Unexplained Key Sequence? - rprosperi - 06-22-2014 05:36 PM
By coincidence, I just got a beautiful HP-80 from TAS 2 days ago, and while playing with it, I entered repeated 8's to verify the LED segments, and discovered it does a similar (by that I mean unexpected) thing.
Initially of course, it fills the display left to right, but once filled, the exponent field grows by 1 for each addional press of 8, or indeed any numeric entry key.
As noted above, just another unexpected result (as opposed to bug I suppose) which was 'corrected' in later models.
Of interest, the s/n begins 1247... meaning one of the earlier units produced, since Introduction was 1973. The HP-35 2.02 bug is well known, but are there analogous HP-80 bugs in history books?
RE: HP-80 Unexplained Key Sequence? - HP67 - 06-22-2014 05:47 PM
Wow, what a beautiful calculator. I had to look that one up. I had not heard about it.
RE: HP-80 Unexplained Key Sequence? - Thomas Klemm - 06-26-2014 04:25 AM
(06-22-2014 05:36 PM)rprosperi Wrote: The HP-35 2.02 bug is well known, but are there analogous HP-80 bugs in history books?
There's a display bug (search for the title: "End Note - Bugs?") and another one concerning \(\Sigma\)+ described in my Message #10 posted on 13 Feb 2012.
Cheers
Thomas