## Welcome to BrainDen.com - Brain Teasers Forum

 Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account. As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends. Of course, you can also enjoy our collection of amazing optical illusions and cool math games. If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top. If you have a website, we would appreciate a little link to BrainDen. Thanks and enjoy the Den :-)
Guest Message by DevFuse

# Rainman

Member Since 30 Jul 2012
Offline Last Active Yesterday, 10:25 PM

### #341914n!+1 is composite

Posted by on 13 March 2015 - 12:09 PM

Spoiler for

• 1

### #341913Apple, blueberry or pumpkin?

Posted by on 13 March 2015 - 11:51 AM

Spoiler for

• 1

### #341796The professor's son.

Posted by on 03 March 2015 - 11:39 PM

Spoiler for

Spoiler for minor correction

• 1

### #341795Checkerboard Challenge

Posted by on 03 March 2015 - 11:30 PM

Spoiler for

• 1

### #341696A mean, mean minimization problem

Posted by on 25 February 2015 - 05:45 PM

Spoiler for

• 1

### #341584Hello guys i have a puzzle/riddle i can not work out

Posted by on 16 February 2015 - 02:17 AM

Spoiler for

• 1

### #337280Inequalities for large integers

Posted by on 29 January 2014 - 12:49 PM

These problems use Knuth's up-arrow notation (http://en.wikipedia....-arrow_notation), with ^ being the up-arrow.

1. Find the smallest value for n, such that 1000^^n > 12^^(n+1).

2. We define the sequence g, by assigning g(1) = 3^^^^3, and g(n+1) = 3^^^...^3, where the number of up-arrows is g(n). A famously large number is Graham's number = g(64). Which is larger, Graham's number or 2^^^...^2, where the number of up-arrows is Graham's number?

• -1

### #336956Can you decript this?

Posted by on 09 December 2013 - 11:26 PM

I don't have friends

That sucks, I don't have many friends myself. Aaryan's point, though, is that asking us to solve it for you is cheating. But since you got the hint of using a 9x6 matrix, I'll at least do you the favor of putting the message in a 9x6 matrix.

WH3TEE
HERWDN
A2OO7T
TSO6AY
0QTHN9
IU4UDF
SAON8I
1RFDTV
TE5RWE

Hopefully you can see it now. Good luck with the competition!

• 1

### #334853Chase on an endless road, continued

Posted by on 30 July 2013 - 04:46 PM

Caught again, your friend concedes that you are the supreme runner. Maybe it's not a coincidence that your profile pic is an ostrich

• 1

### #327168piece of cake

Posted by on 10 January 2013 - 04:44 PM

Spoiler for the cake could look like this

• 1

### #326785Blood runs thick in Transylvania

Posted by on 19 December 2012 - 05:04 PM

• 1

### #326671Amoeba evacuation puzzle

Posted by on 08 December 2012 - 01:18 AM

Yeah I think that is correct, here's why:

Spoiler for

That's the solution I had in mind for the problem, well done. I also enjoyed your javascript implementation of the problem.

• 1

### #326621Amoeba evacuation puzzle

Posted by on 29 November 2012 - 11:01 PM

An amoeba is sitting on the bottom left square (A1) of a chessboard which extends infinitely upwards and to the right. You can make an amoeba split into two. If an amoeba is split into two, its offspring will take the square directly above and the square directly to the right of the parent amoeba. This vacates the square of the parent amoeba. So your first move, splitting the amoeba on A1, will put one amoeba on A2 and one amoeba on B1. An amoeba can only split if both spaces for its offspring are unoccupied. Your objective is for all the amoebas to evacuate the area A1, A2, A3, B1, B2, B3, C1, and C2. (Squares marked with x in drawing below)

...........
oooooooo...
oooooooo...
xxoooooo...
xxxooooo...
xxxooooo...
• 1

### #325187What is the missing term of the sequence?

Posted by on 08 September 2012 - 06:58 PM

Spoiler for

• 1