In order to unblock an IP number, go to [[wikipedia:Blocked IPs]] and remove the corresponding line. The software does not unblock any number automatically: as long as the number is listed under Blocked IPs, it is blocked.
I looked a bit at the oeuvre of that 62.98.* guy. It's quite an interesting case. I don't think he's malicious. You don't enter hundreds of (correct!) digits of pi if you want to discredit a project. He's misguided, for sure. He looks to me like somebody who has had many idiosyncratic ideas brewing in his head for years, and now they pour out in a couple of days. Maybe not unlike our Slovenian Rastafarian prime number lover.
Axel