IP: 141.105.120.nnn (at least 151 and 153)
UA: Mozilla/5.0 (compatible; OpenindexDeepSpider/Nutch-1.5-dev; +http://www.openindex.io/en/webmasters/spider.html)
Recommendation: Block SE server range for Compukos / DirectVPS at 141.105.120.0 - 141.105.127.255
It did seem to go away when I waved a 403 at it.