Converting rational numbers to an “alien” data format
Batch, 531 bytes

@echo off
set q=
set s=
set m=
if %1 lss 0 set m=-
set/ai=%m%%1,n=%2,d=%3,p=0
:i
set/ar=i%%47,i/=47
if %r% gtr 9 set r=[%r%]
set s=%s%%r%
if %i% gtr 0 goto i
:p
if %n%==0 goto n
set/ao=n,g=d%%47
if %g% gtr 0 goto g
set/ap+=1,d/=47,r=n/d,n%%=d
if %r% gtr 9 set r=[%r%]
set s=%r%%s%
goto p
:g
set/aq+=1,p+=1,r=n*47/d,n=n*47%%d
if %r% gtr 9 set r=[%r%]
set s=%r%%s%
if %n% neq %o% goto g
if %q% gtr 9 set q=[%q%]
set q=%q%:
:n
if %p% gtr 9 (set q=%q%-[%p%]:)else if %p% gtr 0 set q=%q%-%p%:
echo #%q%%m%%s%


Takes three parameters, whole number, numerator, denominator representing a mixed number in its lowest terms.