(15/14)n Flips are (almost) Sufficient to Sort Heydari and Sudborough's Pancake Stack

Abstract

We present a flip sequence of length ⌈ (15/14)n + 2 ⌉ for sorting the Heydari and Sudborough's stack of n pancakes, which was introduced to prove the best-known lower bound of (15/14)n for the pancake number of n pancakes.