Big Factorial program for the HP-15C
Description
This program computes the factorial of large numbers up to 1 x 10^8.
It computes the mantissa separately from the exponent. Enter the number to factorialize in the X register. Then press the A function key.
The value in the Y register is the Mantissa, and the value in the X register
is the exponent.
Program resources
Labels
| Name |
Description |
|
| A |
Start the program |
|
Storage Registers
| Name |
Description |
|
| 0 |
The original number |
|
| 1 |
Stores the exponent |
|
Program
| Line |
Display |
Key Sequence |
|
Line |
Display |
Key Sequence |
|
Line |
Display |
Key Sequence |
|
| 000 |
|
|
|
019 |
1 |
1 |
|
038 |
45 0 |
RCL 0 |
|
| 001 |
42.21.11 |
f LBL A |
|
020 |
8 |
8 |
|
039 |
20 |
✕ |
|
| 002 |
44 0 |
STO 0 |
|
021 |
4 |
4 |
|
040 |
40 |
✛ |
|
| 003 |
1 |
1 |
|
022 |
0 |
0 |
|
041 |
45 0 |
RCL 0 |
|
| 004 |
2 |
2 |
|
023 |
20 |
✕ |
|
042 |
43 26 |
g π |
|
| 005 |
20 |
✕ |
|
024 |
1 |
1 |
|
043 |
20 |
✕ |
|
| 006 |
15 |
1/x |
|
025 |
3 |
3 |
|
044 |
2 |
2 |
|
| 007 |
45 0 |
RCL 0 |
|
026 |
9 |
9 |
|
045 |
20 |
✕ |
|
| 008 |
43 11 |
g x² |
|
027 |
34 |
x↔y |
|
046 |
11 |
√x̅ |
|
| 009 |
2 |
2 |
|
028 |
10 |
÷ |
|
047 |
43 13 |
g LOG |
|
| 010 |
8 |
8 |
|
029 |
30 |
− |
|
048 |
40 |
✛ |
|
| 011 |
8 |
8 |
|
030 |
1 |
1 |
|
049 |
44 1 |
STO 1 |
|
| 012 |
20 |
✕ |
|
031 |
40 |
✛ |
|
050 |
42 44 |
f FRAC |
|
| 013 |
15 |
1/x |
|
032 |
43 13 |
g LOG |
|
051 |
13 |
10ˣ |
|
| 014 |
40 |
✛ |
|
033 |
45 0 |
RCL 0 |
|
052 |
42 31 |
f PSE |
|
| 015 |
45 0 |
RCL 0 |
|
034 |
1 |
1 |
|
053 |
45 1 |
RCL 1 |
|
| 016 |
3 |
3 |
|
035 |
12 |
ℯˣ |
|
054 |
43 44 |
g INT |
|
| 017 |
14 |
yˣ |
|
036 |
10 |
÷ |
|
055 |
43 32 |
g RTN |
|
| 018 |
5 |
5 |
|
037 |
43 13 |
g LOG |
|
|
|
|
|