How to create a matrix?

Hi all, I am trying to create a matrix (101x101) like this :

Can anyone help me with the code please?

Answer 1

[Azzi Abdelmalek]

n=4  % in your case use n=101
out=tril(2*ones(n),-1)

[jack star]

Thank you very much for your answer.

Now I'm trying to solve this matrix:

Y= U x g

% Y(101x1) and U(101x101) matrixes.

to find g, i used this g = inv(U)*Y

But it found g(101x1) NaN matrix. You have any idea why?