1 + k - ( floor([1+sqrt(1+8k)]/2) [ floor([1+sqrt(1+8k)]/2) - 1 ] / 2 ), k=1..100

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.