How to create a specific Matrix

Hi !

Can anyone help me in builting this specific matrix? I do not know if the "randi" function is the exact one.

Thank you in advance for your help!

Answer 1

[KSSV]

c = [1 1 2 2 3 3]' ; 
iwant = repmat(l',1,4) ;

Answer 2

[Bhaskar R]

M = repelem([1:3]', 2, 4)

[Sara Trova]

Thank you very much!!