The Museum of HP Calculators

# Permutation for the HP-25

This program is Copyright © 1975 by Hewlett-Packard and is used here by permission. This program was originally published in "HP-25 Applications Programs".

This program is supplied without representation or warranty of any kind. Hewlett-Packard Company and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.

## Overview

A permutation is an ordered subset of a set of distinct objects. The number of possible permutations, each containing n objects, that can be formed from a collection of m distinct objects is given by

```                 m!
mPn = ------- = m(m-1) ... (m-n+1)
(m-n)!

```

where m, n are integers and 0 < = n <= m.

Notes:

1. mPn can also be denoted by Pmn,  P(m,n) or (m)n.

2. mP0 = 1,   mP1 = m,   mPm = m!

## Instructions

 Step Instructions Input Data/Units Keys Output Data/Units 1 Enter program 2 Store m, n m STO 0 n STO 1 3 Compute permutations f PRGM R/S mPn 4 For new case, go to step 2

## Examples

1. 43P3 = 74046.00
2. 73P4 = 26122320.00

## The Program

```LINE    CODE    KEYS
00
01     24 00   RCL 0
02     24 00   RCL 0
03     24 01   RCL 1
04     15 71   g x=0
05     13 29   GTO 29
06     14 71   f x=y
07     13 31   GTO 31
08     14 51   f x>=y
09     13 39   GTO 39
10        01   1
11     14 71   f x=y
12     13 41   GTO 41
13        22   roll dn
14        41   -
15        01   1
16        51   +
17        61   x
18     14 73   f LASTx
19     24 00   RCL 0
20        01   1
21        41   -
22     14 71   f x=y
23     13 26   GTO 26
24        22   roll dn
25     13 15   GTO 15
26        22   roll dn
27        22   roll dn
28     13 00   GTO 00
29        01   1
30     13 00   GTO 00
31        01   1
32        41   -
33     15 71   g x=0
34     13 37   GTO 37
35  23 61 00   STO x 0
36     13 31   GTO 31
37     24 00   RCL 0
38     13 00   GTO 00
39        00   0
40        71   ÷
41        22   roll dn
42        22   roll dn
43     13 00   GTO 00
```

```R0  m
R1  n
```