Hi,

 

Is it possible to write a function which gives the following result:

((1)(1 2 2)(1 2 2 3 3 3)(1 2 2 3 3 3 4 4 4 4)(1 2 2 3 3 3 4 4 4 4 5 5 5 5 5))etc.

 

Thanks for any suggestions!

(defun generate (n)
  "Generate a nested list where each sublist expands with numbers repeating themselves."
  (loop for i from 1 to n
        collect (loop for j from 1 to i
                      append (make-list j :initial-element j))))

 

Thank you Stephane for the veery quick response!!