In the infinite series 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 5... each positive integer k appears k times in consecutive order.

Write a formula for the sum of the first n terms of the series.

(In reply to A formula by Dej Mar)

Sloane A060432

The summation from 0 to k doesn't make sense.

...and "n" doesn't appear anywhere in your formula.  How can you find the first n terms without specifying the value of n?

Edited on May 17, 2007, 12:45 am

Posted by Mindrod on 2007-05-14 21:04:52