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+--- Thread: (12C Platinum) Reverse Factorial (/thread-11853.html)
(12C Platinum) Reverse Factorial - Gamo - 11-27-2018 08:29 AM
Just acquired a brand new HP-12C Platinum and here is the first program for it.
This program also work on original HP-12C.
Program is use for reverse factorial.
If you know the number of ways and need to know what is the value of its Factorial.
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Procedure:
Integer [R/S] display Factorial Integer
If Integer is not a perfect Factorial the answer will display "negative" Factorial integer,
then switch stack display the + or - integer.
Integer [R/S] display Negative Factorial [X<>Y] +or- Integer
Remark: The negative result indicate that this is not a perfect factorial.
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Example:
120 is what Factorial?
120 [R/S] display 5
Answer: 5!
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555 is what Factorial?
555 [R/S] display -5 [X<>Y] 435
Answer: 5! + 435
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Program: Reverse Factorial (RPN Mode)
Code:
001 STO 0
002 STO 1
003 2
004 STO 2
005 RCL 0
006 RCL 2
007 ÷
008 STO 0
009 RCL 2
010 X<>Y
011 X≤Y
012 GTO 016
013 1
014 STO+2
015 GTO 005
016 1
017 RCL 0
018 -
019 X=0
020 GTO 028
021 RCL 1
022 RCL 2
023 n!
024 -
025 RCL 2
026 CHS
027 GTO 000
028 RCL 2Program for ALG Mode
Code:
001 STO 0
002 STO 1
003 2
004 STO 2
005 RCL 0
006 ÷
007 RCL 2
008 =
009 STO 0
010 RCL 2
011 X<>Y
012 X≤Y
013 GTO 017
014 1
015 STO+2
016 GTO 005
017 1
018 -
019 RCL 0
020 =
021 X=0
022 GTO 031
023 RCL 1
024 -
025 RCL 2
026 n!
027 =
028 RCL 2
029 CHS
030 GTO 000
031 RCL 2Gamo