All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Numbers > Sequences
Repeated addition (Posted on 2004-02-20) Difficulty: 4 of 5
+
+=
++=
+=
++++=
+===+=
++++++=
+=
++=
+=+===+=+=
++++++++++=
+===+=

Explain the pattern and find the next five rows.

Hint: the symbols I chose have nothing to do with the pattern.

See The Solution Submitted by Tristan    
Rating: 4.3333 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Solution No Subject | Comment 4 of 14 |
The below formula might seem complicated but actually it isn't!
It is presented as an algorithm,whereas "s" is the sequence number and "x" is the position(number) of each element in the sequence.

The first element is always +
Now the loop :

>For x=2 to s do

>If x a prime :
> If (s)modulo(x)=0 then
> we have a "="
> If s is a power of x then exit loop
> Else we have a "+"
>If x not a prime :
> If any of the factors of x has a "=" then
> we have a "="
> If (s)modulo(x)=0 then exit loop
> Else we have a "+"

The 17 first sequences :

1) +
2) +=
3) ++=
4) +=
5) ++++=
6) +===+=
7) ++++++=
8) +=
9) ++=
10) +=+===+=+=
11) ++++++++++=
12) +===+=
13) ++++++++++++=
14) +=+=+===+=+=+=
15) ++=+==++==+=++=
16) +=
17) ++++++++++++++++=

I was too lazy to test it for all the sequences so I'm not 100% sure...
  Posted by es_rever on 2004-02-20 22:16:32
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (4)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information