Challenge: Generate 24 in the X register / display

09082020, 01:40 PM
Post: #41




RE: Challenge: Generate 24 in the X register / display  
09082020, 03:09 PM
Post: #42




RE: Challenge: Generate 24 in the X register / display
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Hi, Gene & all: Quote:Challenge: Using a single digit repeated 3 and only 3 times, produce the number 24 in the X register As no one has submitted a solution for the HP71B (as if !), here's a generic one I've created for it: DISP USING "^,DD";(digit+digit)/digit,FACT(RES+RES) 24 Simple as it is, notice the following:  it meets all requirements but as the HP71B doesn't have an "X register" it simply puts 24 in the display  it works in any FIX, SCI or whatever mode so it puts in the display 24, not 2.4000E1 or 24.00  it doesn't use any other numbers at all, nor any variables  as per the requirements, it works for digit = 1,2,3,..., 9, but also you can replace digit by most any number, be it Pi, Sqrt(5), e^Pi^Pi, ..., except digit = 0  for digit = 0, substitute digit above by, say, EXP(digit) or COS(digit), and there you are.  also, RES+RES could be instead RES*RES, RES^RES, and other variants. This solution can be adapted easily to most RPN models, for instance: digit, ENTER, digit, +, digit, / , x^2, FACT Thanks for the challenge and best regards. V. All My Articles & other Materials here: Valentin Albillo's HP Collection 

09082020, 03:38 PM
Post: #43




RE: Challenge: Generate 24 in the X register / display
My apologies for this answer: I did not have the time to participate, and before reading the above answers I post mine. Sorry if I’m repeating answers or giving some already found (and I guess I’m far from the best answers).
Tested on HP42s but did not want to use STO+X to make it work on 15c or other classic RPN. That said, here are my attempts: Code:
Now I can’t wait to see the answers for 9 and 0! Thibault  not collector but in love with the few HP models I own  Also musician : http://walruspark.co 

09082020, 04:00 PM
Post: #44




RE: Challenge: Generate 24 in the X register / display
And now I’ve read the above messages and noticed that the rules, apparently clear and simple, were not.
Was it asked to find a solution for each digit from 0 to 9 as I did, or the best solution using 1 of the digits? I also understand that each digit had to be used 3 and only 3 times, and I respected the rule with a few cheating, letting the unused digits on the stack (ie. 5). Thibault  not collector but in love with the few HP models I own  Also musician : http://walruspark.co 

09082020, 04:21 PM
Post: #45




RE: Challenge: Generate 24 in the X register / display
The goal was to use each digit exactly 3 times, no more and no less.
Ideally 10 solutions, one for 0 through 9. A general solution is possible  get a number 4 showing in the display and use FACT or n! (if available on the model) to get to 24, but that may be more steps than another solution. 

09082020, 04:56 PM
Post: #46




RE: Challenge: Generate 24 in the X register / display  
09082020, 06:01 PM
Post: #47




RE: Challenge: Generate 24 in the X register / display
(09082020 01:40 PM)Gene Wrote:(09082020 12:04 AM)Dwight Sturrock Wrote: HP42S, 5 steps: Oops, think I was sidetracked by the exception for PI. HP42S, 6 steps using 4 three times: OCT 4 ENTER ENTER X + 

09082020, 08:32 PM
Post: #48




RE: Challenge: Generate 24 in the X register / display
Found new ideas
1) 5 steps Code:
2) 3 steps Code:
3) 4 steps Code:
4) 6 steps Code:
5) 7 steps Code:
6) 5 steps Code:
7) 8 steps Code:
8) 5 steps Code:
9) 7 steps Code:
10) 10 steps Code:
Thibault  not collector but in love with the few HP models I own  Also musician : http://walruspark.co 

09092020, 06:39 AM
Post: #49




RE: Challenge: Generate 24 in the X register / display
(41, 42) generic solution for d=1..9, shamelessly borrowing pinkman's idea:
Code: dd 

09092020, 04:29 PM
(This post was last modified: 09092020 04:30 PM by pinkman.)
Post: #50




RE: Challenge: Generate 24 in the X register / display
Excellent! This uses dd/d=11, thus (dd+d)/d=12
The same for 15c and others without STO X function: Code:
Thibault  not collector but in love with the few HP models I own  Also musician : http://walruspark.co 

09092020, 08:14 PM
Post: #51




RE: Challenge: Generate 24 in the X register / display
(hp50)
#1  1 10^x EULER 1 %T 1 –  #2  2 DUP DUP ➝LIST ΣLIST !  And a general solution for any three equal numbers (including zero) placed on the stack:  N DUP DUP MAX SAME 10^x EULER !  or  N DUP DUP MAX SAME 10^x √ e^x CEIL  

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