## 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

# No First-Hand-Neighbors & Second-Hand-Neighbors!!!

5 replies to this topic

Senior Member

• Members
• 1702 posts
• Gender:Female

Posted 06 July 2013 - 09:22 PM

Create the shortest possible sequence such that no number is next to its first-hand or second-hand neighbors (e.g., the number 3 cannot be next to numbers 1, 2, 4, or 5, which are first- and second- neighbors).

• 0

### #2 Nins_Leprechaun

Nins_Leprechaun

Junior Member

• Members
• 37 posts

Posted 06 July 2013 - 10:46 PM   Best Answer

Spoiler for

• 0

Senior Member

• Members
• 1702 posts
• Gender:Female

Posted 06 July 2013 - 11:50 PM

Spoiler for

is a 5 sequence possible?

• 0

### #4 Nins_Leprechaun

Nins_Leprechaun

Junior Member

• Members
• 37 posts

Posted 07 July 2013 - 01:12 AM

Spoiler for

is a 5 sequence possible?
No as there would be a number that could not be beside any other. For example in a sequence of numbers 1-5 the number 3 could not be beside any other number making a run of 5 (or less) impossible.
• 0

### #5 bonanova

bonanova

bonanova

• Moderator
• 5918 posts
• Gender:Male
• Location:New York

Posted 07 July 2013 - 06:09 AM

• 0
The greatest challenge to any thinker is stating the problem in a way that will allow a solution.
- Bertrand Russell

Senior Member

• Members
• 1702 posts
• Gender:Female

Posted 07 July 2013 - 04:54 PM

i should have been more clear in the op, the sequence must start at 1 and go to some n greater than 1 (consecutively).

• 0

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users