Easiest way to find out if your site is banned: try a search where your site would be the only one that would match. Such as a complete sentence in quotes. If your site comes up for that search, it is indexed by Google. Note that if the site doesn't come up, it doesn't mean it necessarily was banned. Googlebot may not have yet found the site; or if it had previously on the last crawl was unable to reach the server for some reason.