What's wrong with this cron entry?

Question

Task Schedulers

Hello everyone,
the task is to execute a python script every first Monday of the month. The solution is this line in crontab, verbatim -

00  09  1-30 *  *  [ $(date +\%a) = Mo ] && python /www/manage.py act_monthly_report

However, it doesn't work. At the same time, the line CRON[10889] appears in the syslog: (www) CMD ([ $(date +%a) = Mo ] && python /www/manage.py act_monthly_report) - that is, the condition is met. And the script is also fine, if you call "python /www/manage.py act_monthly_report" from the shell, it will work without problems. Together they don't want to.
What can a dog be buried in?
PS. Ubuntu 12.04, if anything.

Answer 1

echo $(date +\%a)
Mon