How to make cron pull the script every 90 days?

Question

Task Schedulers

Good afternoon!
There is a script that needs to be pulled every 90 days, as I understand it, it will not work to explicitly indicate 90 days, but I realized that you can do the first day of every third month, tell me how the record will look like !?
I guess the entry should be:
0 10 */3 * * /bin/bash /etc/apache2/ssl/certbot-auto renew --quiet --no-self-upgrade

Answer 1

Tool to help crontab-generator.org
* * * 1,4,7,10 * run >/dev/null 2>&1