Create a vector with specific intervals

I want to create two vectors. vectors are like following

limit = 100; % limit can be any number

a = [1,4,5,8,9,12,13 ..... limit]

b = [2,3,6,7,10,11,.........limit]

Answer 1

[Mohammad Sami]

You can split it into 4 sequences. then merge it back together to create your desired vector.

limit = 100;
a1 = 4:4:limit;
a2 = 5:4:limit;
b1 = 2:4:limit;
b2 = 3:4:limit;
a = sort([1 a1 a2]);
b = sort([b1 b2]);