how to create an array from a given array with the following criteria.

Say given array is [1 2 3]. I want to create an array with the elements [1 2 3 4 5 2 3 4 5 6 3 4 5 6 7],

In others terms I want to create an array [1:1+4 2:2+4 3:3+4]

I do not want to use for loops as that slows my code considerably.

Answer 1

[madhan ravi]

a = 1:3
Wanted = reshape(cumsum([a; ones(4,numel(a))]),1,[])

Answer 2

[Ameer Hamza]

An alternative solution using automatic array expansion

a = 1:3;
b = reshape(a + (0:4)', [], 1);