Because by default, the series (0,1,2,4,8,16) are **Category labels** rather than **values** in Excel, so no matter how the big the number is, they will be equally spread.

What you want to do is to make the X-axis linear, so instead of considering the series as category labels, they will be seen as real numbers.

Mepher above already answered how you can do this in Excel. But if you want another more versatile solution, you could try to use an Excel add-in called FunFun, it allows you to use JavaScript directly in Excel so that you could use powerful libraries like D3.js or Chart.js to make different charts.

In the link below, I made a chart with FunFun playground, you could see the labels X-axis are **spreading linearly** according to their values.

https://www.funfun.io/1/edit/5a27fb06cf76561801b73335

You could also link this result directly to your Excel by URL. Here are some screenshots of how it looks like in Excel.

*Disclosure: I'm a developer of Funfun*