Printing large integers to file in GAP without linebreaks

Question

In GAP (http://www.gap-system.org/), I want to print large numbers to files without line breaks (to match the format for the b-files at Sloane's encyclopedia, for example: b000186.txt).

However, if I use AppendTo("<filename>",n," ",f(n),"\n"); when f(n) is a large number, it adds linebreaks, which I don't want. Is there an easy way to avoid these?

I've tried writing functions that give the digits of f(n), but they eventually hit "recursive death traps".