puzzle game collection

http://www.shockwave.com/japan/index.html

puzzle game

http://pc.kiteretsu.jp/games/zka/zka.swf

puzzle game

http://cyber.chongju.ac.kr/~ivory/game/pyramid.swf

QUIZ : What is the missing number in this logical series?

This is a mathematical challenge, and it's been said that:

If you're an engineer, you should be able to solve it in (under) three minutes,
If you're an architect, in three hours;
If you're a doctor, in six hours;
If you're an accountant, in three months and
If you're a lawyer, probably never.

What is the missing number in this logical series?
1, 2, 6, 42, 1806, ____???

defense game

game guide : http://armorgames.com/guide/gemcraft-zero-gem-of-eternity-guide?gc0=mainMenu