What does "-4^(1/4)" mean and why is it connected to porn?

Answer (1 of 6): (only anon because I want "[my name] pornography" to have zero google hits at least until I have tenure) Note: this answer has been updated several times as I've experimented further and responded to comments. I highly doubt those results are coming from that formula per se, as...

[tmatsuu]

Googleで"-4^(1/4)"で検索するとなぜかエロサイトが検索結果にでてくる。日本語のGoogleでも出てきた。Googleエンジニアいわくバグらしい。

[mickn]

What does "-4^(1/4)" mean and why is it connected to porn?

[AKIMOTO]

http://developer.cybozu.co.jp/akky/2013/02/googling-equation-gives-you-porn/