Problem in pettern question

question: Write a program to print the pattern:
1 2 3 4 17 18 19 20
5 6 7 14 15 16
8 9 12 13
10 11
it also has space in the beginning of line 2,3 and 4 has 2,4 and 6 spaces .
In this question i am not able to print the 11,12,13,14,…20 digits please tell me how i can print this???