Can I Create a Pattern with Alternating 1's and 0's in Mathematica?

[Sarah rob]

I am using
co = 0;
co++
If[Mod[co, 20, 1] > 10, 1, 0];
which is used in an iterative function
which produces 10 1' s 10 0' s, 10 1' s 10 0' s and so on ...
Could I use a similar method to produce 10 1' s then 5 0' s, 10 1's 5 0' s and so on...

 

[Bill Simpson]

co = 5;co++;If[Mod[co, 20, 1] > 5, 1, 0]