$; is used as an ordinary variable. It could have been $f. For each character in the string, if zero it is replaced by 3, if 3 it is replaced by 30, thus yielding the sequence 3, 30, 303, 30330, 30330303. Each value is simply the concatenation of the previous two values; for example, 30330303 is 30330 followed by 303. Thus, its length is the sum of the two previous lengths, yielding Fiboncci numbers. If you replace 0's by newborn and 3's by old rabbits you get Fibonacci's model of population growth

I tried to execute this on ActiveState Win32 v5.10.0 and received the following error message:

Can't find string terminator "'" anywhere before EOF at -e line 1.
The filename, directory name, or volume label syntax is incorrect.
[download]

I copied the code exactly as written, there are 2 string terminators in the line of code.

Any suggestions?

Thanks

I haven't used windows in about 10 years, but a voice in my head says that windows may not support single quotes for command-line arguments. Try using double quotes instead? In unix systems, double quotes will cause $variables to be interpolated so I used single quotes.

blokhead

Thanks, it works now, I keep forgetting about those pesky double quotes.

30 was pretty fast for me, but 48 is taking a bit of time...

pmonk4ever

"No trees were harmed in the creation of this node. However, a rather large number of electrons were somewhat inconvenienced."