Posted by **Diana** on Sunday, October 4, 2009 at 6:46pm.

The first three elements of a number sequence are 1, 2, 3. ( As you can see, the middle number is one less than the product of its neighbors. This is true for the rest of the elements of this sequence. Now add the elements of the sequence up to a certain element. Could this sum be 2009? Could this sum be 2010?

- Math -
**Reiny**, Sunday, October 4, 2009 at 6:58pm
the sequence runs this way :

1 2 3 2 1 1 2 3 ..

it repeats!

the first loop is 1 2 3 2 1

the sum of that loop is 9

so as long as we add up to the end of a loop we have multiples of 9

If we add up 223 loops the sum is 2007

adding the next digit, which is a 1 would give up 2008, and if we add the next one after that, we would get 2010

So it is not possible for a sum of 2009, but we will reach 2010

- Math -
**Diane**, Sunday, October 4, 2009 at 7:11pm
THANK YOU! =)

## Answer This Question

## Related Questions

- math - write each expression using n as your variable.then simplify fully. 1....
- MATH - the first number of a sequence is 200. every number of the sequence after...
- math - the first number of a sequence is 200. every number of the sequence after...
- maths - three number form an arithmetric sequence. Their sum is 24. A)If 'a' is ...
- algebra - Five times the smallest of three consecutive odd integers is ten more ...
- Algebra/Number Theory - In a sequence of four positive numbers, the first three ...
- computer science programming - Elements – sequence-series outputting Write a ...
- math - What is the rule for this sequence? 72 , 63 , 54 , 45 , 36 Each number ...
- math - Three numbers in an arithmetic sequence sum to six. If you add 1 to the ...
- Algebriac Expressions - 2 less than 7 times a number = 2) Sarah's age decreased ...

More Related Questions