HP-80 Unexplained Key Sequence? - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: General Forum (/forum-4.html) +--- 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 sequencesâ€¦ 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