API that returns IPv4 prefixes for a particular BGP AS number

Hello,

I am wondering if there is any API available to retrieve a list of IPv4 prefixes for a given BGP AS number. I know there are public internet route servers where one can run a "show ip bgp" type command with filters (regular expressions) to see a list of prefixes originated by a particular AS number. I am interested in finding out a programmatic way of retrieving prefix list perhaps as a JSON output. I am not looking for any paid service, I just need to use it one time only.

Thanks for looking into this.