Parker introducerede konceptet '''grafting number''' til [[rekreationel matematik]], hvor et [[heltal]] med den egenskab at [[kvadratrod]]en af heltallet, når det udtrykkes i base ''b'', vil indeholde det oprindelige heltal eller direkte efter kommaet.<ref>{{cite AV media|series=Numberphile|title=98 and Grafting Numbers – Numberphile|date=2012-01-20|url=https://www.youtube.com/watch?v=hiOMtBrH8pc|accessdate=2017-05-15}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=wK2MAwAAQBAJ|title=Things to Make and Do in the Fourth Dimension: A Mathematician's Journey Through Narcissistic Numbers, Optimal Dating Algorithms, at Least Two Kinds of Infinity, and More|last=Parker|first=Matt|date=2014-12-02|publisher=Farrar, Straus and Giroux|isbn=978-0-374-71037-8|pages=62, 63|language=en}}</ref><ref>{{Cite journal|last=Tanniru|first=R|date=2015|title=A short note introducing Grafting Numbers and their connection to [[Catalan number|Catalan Numbers]]|url=|journal=[[Journal of Combinatorial Mathematics and Combinatorial Computing]]|volume=95|pages=309–312}}</ref>
Levende_personer Matematik Subkulturer