You want to need a crontab job Configuration on AIX, you can see below.
Day of the month [1,31]
Month of the year [1,12]
Day of the week ([0,6] with 0 or 7 =Sunday)
Clean up core files every weekday morning at 3:15 am:
15 3 * * 1-5 find $HOME -name core 2>/dev/null | xargs rm -f