How to make vector increasing same value??

For example, I have a vector [1,2,3,4]

But, I want to increase this like

[1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4]

I tried to if and for. But it doesn't work well.

Could you recommend something?

Answer 1

[Stephen23]

repelem([1,2,3,4],4)