I want to set up a cronExp to run 1 am on a particular day of the month which is added from a query 

```
cronExp = "0 0 1 "+@auto.Day+ "* *";

```

I tried the above but I get this not syntactically correct

Please help

Update 

I managed to make below work auto.Day =24

```
cronExp = "0 1 1 */"+@auto.Day+" *";

```

but it reads Cron At 01:01 AM, every 24 days is this the same as 01:01 Am on the 24th of everymonth?