OEIS shows the number of groups of order $n$ upto $2047$. The Magma-online-calculator uses a database, but already for $1024,2004,2016,...$ it cannot determine the number of groups. Maple seems to calculate the number of groups (unless it is too large), but unfortunately, I do not have access to maple.
Does anyone know an online-calculator for the number-of-group-function, or a table with the known numbers upto $10,000$ or more ?
Or alternatively, allows PARI/GP, at least in principle, to calculate the number of groups of order $n$ ? I programmed the case $n$ squarefree, but I have no clue how to manage arbitary numbers $n$.