The first three seeds (in hexadecimal) for all 3 of the GBA games are: 1496, 90EA, 3671
Put these in boxes A1, A2, A3 in an excel spreadsheet
After that, the next seed is calculated by BITXOR(BITRSHIFT(A3,5)+MOD(BITRSHIFT(A2,-11),65536),MOD(BITRSHIFT(A1,-1),65536)+BITRSHIFT(A2,15))
and so on, so you can place that in A4 and then just drag down as far as you want.
You can then get the actual RN numbers by converting each of these to decimal (hex2dec) and diving by 65535/100 and rounding down.
ruadath's post in FE8 RNG Seed/Formula/List? was marked as the answer