New to crontab, I wanted to experiment.
Running the command
crontab -l gave me the following answer
crontab: no crontab for User_1
Every time I tried to issue a command like
1 16 24 10 6 ping -D -c 1 www.google.com I got the error "zsh: command not found".
Every time I modified the first number of the crontab command I got an error message saying, if for example 15 is the first number of the command,
zsh: command not found: 15.
Mac OS X 10.12.6. zsh 5.8
/usr/bin is in my path.