You can't specify in the cron schedule for the day of week to be divided unlike some of the other schedules, nor can you use the # to get consistent results.
The answer is to use an epxression in cron command:
0 10 * * 1 [ `expr \`date +\%s\` / 86400 \% 2` -eq 1 ] && <my command>
This will run this command every monday and by determining whether it's an odd or even day since the unix epoch will run the command
To determine whether a command would run on a specific day use the following command:
expr `date +%s -d "today"` / 86400 \% 2
a 1 means it will run a 0 means it won't. Adjust the
-eq 1 to
-eq 0 to adjust the day the command runs on.