hi there,
I've read a manga quite some time ago, I'm sure it was mature. Or seinen or sth. But surely not hentai, yaoi or yuri. Also no shoujo ai, shounen ai.

What I remember:
We've got three important guys: One master thief, one extreme math-lover and one girlie who seduces the men for their plans. She distracted them at the very beginning already. Anyway, girlie sleeps & adores math - that's also his nickname - and also seduces the thief.
Their plan: Getting into some big university (I believe it was Tokyo U.?). For that they need the solutions to the questions which they want to get from some yakuza guy.

Rings a bell? Please tell me, I've been wondering since some time now... =) Thanks already

War Front on Spike Hills?

Yosh! That's it - now I know why I never found it on my reading list... it was never there xD
Thanks a lot!! =D