MathDB

On the computer screen there are initially two

1

's written. The insert program causes the sum of those numbers to be inserted between each pair of numbers by pressing the

Enter

key. In the first step a number is inserted and we obtain

1-2-1

; In the second step two numbers are inserted and we have

1-3-2-3-1

; In the third, four numbers are inserted and you have

1-4-3-5-2-5-3-4-1

; etc Find the sum of all the numbers that appear on the screen at the end of step number

25

1