Divide 1 to 39 into 13 scales

Divide the numbers from 1-39 into 13 scales, with each scale representing the following numerical intervals:

Size 1st: 1 - 3

Size 2nd: 4 - 6

Size 3rd: 7 - 9

Size 4th: 10 - 12

Size 5th: 13 - 15

Size 6th: 16 - 18

Size 7th: 19 - 21

Size 8th: 22 - 24

Size 9th: 25 - 27

Size 10th: 28 - 30

Size 11th: 31 - 33

Size 12th: 34 - 36

Size 13th: 37 - 39