python - Consecutive numbers list where each number repeats -

how can create list of consecutive numbers each number repeats n times, example:

list = [0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,5,5] 

another idea, without need other packages or sums:

[x//n x in range((m+1)*n)] 

where n number of repeats , m maximum value repeat. e.g.

n = 3 m = 5 [x//n x in range((m+1)*n)] 

yields

[0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 5]