How to create this monotonically increasing list of numbers?

I want to use a vector V of length N

V = [1 1 2 1 2 3 1]

to create a monotonically increasing list L, where the values of L are as follows:

L = [1 2 3 3 4 5 5 6 6 6 7]

So the entries 1:N of V dictate how many times V(N) is listed sequentially in L,

i.e. the 1st entry in V is listed in L a total of V(1) times..., the nth entry of V is listed in L a total of V(n) times.

Answer 1

[Paolo]

 V = [1 1 2 1 2 3 1]
 n = 1:numel(V);
 L = repelem(n,V)

Answer 2

[Michiele Ogbagabir]

Here is one way

V = [ 1 1 2 1 2 3 1];
L = [];
for i = 1:length(V)
    L = [L repelem(i, V(i))];
end
L