n=6;
AA=ones(2*n,2*n);
BB=zeros(n,n)

BB =

     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0
     0     0     0     0     0     0

A=AA;
A(1:2:end,2:2:end)=BB

A =

     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1
     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1
     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1
     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1
     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1
     1     0     1     0     1     0     1     0     1     0     1     0
     1     1     1     1     1     1     1     1     1     1     1     1

A(2:2:end,1:2:end)=BB

A =

     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1
     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1
     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1
     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1
     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1
     1     0     1     0     1     0     1     0     1     0     1     0
     0     1     0     1     0     1     0     1     0     1     0     1

x=(2:(n+1))

x =

     2     3     4     5     6     7


X=[x;ones(n-1,n)]

X =

     2     3     4     5     6     7
     1     1     1     1     1     1
     1     1     1     1     1     1
     1     1     1     1     1     1
     1     1     1     1     1     1
     1     1     1     1     1     1

P=cumsum(X)

P =

     2     3     4     5     6     7
     3     4     5     6     7     8
     4     5     6     7     8     9
     5     6     7     8     9    10
     6     7     8     9    10    11
     7     8     9    10    11    12

A(2:2:end,2:2:end)=P

A =

     1     0     1     0     1     0     1     0     1     0     1     0
     0     2     0     3     0     4     0     5     0     6     0     7
     1     0     1     0     1     0     1     0     1     0     1     0
     0     3     0     4     0     5     0     6     0     7     0     8
     1     0     1     0     1     0     1     0     1     0     1     0
     0     4     0     5     0     6     0     7     0     8     0     9
     1     0     1     0     1     0     1     0     1     0     1     0
     0     5     0     6     0     7     0     8     0     9     0    10
     1     0     1     0     1     0     1     0     1     0     1     0
     0     6     0     7     0     8     0     9     0    10     0    11
     1     0     1     0     1     0     1     0     1     0     1     0
     0     7     0     8     0     9     0    10     0    11     0    12