(42S/DM42/Free42/Plus42) Birthday Probability Function

[Thomas Klemm]

For small values we can also use:

Code:

00 { 9-Byte Prgm }
01 RCL ST Y
02 X<>Y
03 PERM
04 X<>Y
05 LASTX
06 Y↑X
07 ÷
08 END

Examples

365 ENTER
40 R/S

0.10877

4 ENTER
3 R/S

0.37500