Quote:
Originally Posted by Vindikorr
Yes it is, you win the cookie
Please post in spoiler tags just in case people want to work it out themselves

Okay, here goes:
The first number is 4, whose square root is 2.
Then 16, whose square root is 4.
Then 36, whose square root is 6.
Then 64, whose square root is 8.
Then 100, whose square root is 10.
So... the sixth number is the square of 12.
