Puzzle--- shooting the captives

[devayaani]

Can anyone tell me if there is a formula to find answer to this question?
QUESTION: One thousand enemies are caught by the tribal men. There are exactly one thousand pillars arranged in a circle. They are all asked to occupy the place at one of these thousand pillars. The captor chief orders his assistant to shoot and kill alternate captive standing in a circle of thousand people. They are going to shoot the man at the pillar number one to start the killing. Then number 3, 5, 7 etc. This goes on and on until only one man is standing alive. Who would be the last person alive? (ie which pillar is the man standing at?)
Thanks for the answer and the method to find the answer.
devayaani

[MarkyP05]

Assuming i've worked out the question correctly i'd say the answer was pillar 800. Here's how

Lets make the question smaller and say 10 people & pillars

1,2,3,4,5,6,7,8,9,10

First shooting leaves

2,4,6,8,10

Now this is where I hope ive worked it out right. Shooting now begins with the first person (then 3rd, 5th etc) left alive after round one. If thats correct then the second shooting leaves

4, 8

Now person 4 would be shoot as they are first person left alive. Number 8 is left.

Ive tried this with 20 people and number 16 is left.

If 8 is left with 10 and 16 is left with 20 then this is equal to the person at the 80% mark.

Therefore if there is 1000 enemies then 80% is 800.

Hope this helps . let me know if you find out otherwise.

[Fair-Stumped]

Tried shooting the captives in a spreadsheet (deleted every other number as I progressed across the columns)and got the last eight to be shot as (in order)

80
336
592
848
208
464
720
976 is last man standing

Dont know about a formula though.