Number Knot: free puzzle app for iphone, ipad

Geoff Austin's puzzle Number Knot.The object is to place the numbers into the grid so they form a chain from 1 to n. It's a lot like Marilyn vos Savant's Numbrix. Her puzzle is syndicated weekly in Parade Magazine, which is usually part of a Sunday newspaper. In New York, I believe the NY Post carries it. 

There are 36 free levels and I've done them all. I like it. There are in-app purchases to unlock additional levels.

It's a lot like Marilyn vos Savant's Numbrix. Her puzzle is syndicated weekly in Parade Magazine, which is usually part of a Sunday newspaper. In New York, I believe the NY Post carries it. 
https://itunes.apple.com/app/id972443908
http://www.codejuggler.com/number-knot/