Editing Octahedral number (section)

==History==
The first study of octahedral numbers appears to have been by [[René Descartes]], around 1630, in his ''De solidorum elementis''. Prior to Descartes, figurate numbers had been studied by the ancient Greeks and by [[Johann Faulhaber]], but only for [[polygonal number]]s, [[pyramidal number]]s, and [[Cube (algebra)|cubes]]. Descartes introduced the study of figurate numbers based on the [[Platonic solid]]s and some of the [[Semiregular polyhedron|semiregular polyhedra]]; his work included the octahedral numbers. However, ''De solidorum elementis'' was lost, and not rediscovered until 1860. In the meantime, octahedral numbers had been studied again by other mathematicians, including [[Friedrich Wilhelm Marpurg]] in 1774, [[Georg Simon Klügel]] in 1808, and [[Sir Frederick Pollock, 1st Baronet|Sir Frederick Pollock]] in 1850.<ref>{{citation|title=Descartes on Polyhedra: A Study of the "De solidorum elementis"|title-link=Descartes on Polyhedra|first=Pasquale Joseph|last=Federico|author-link=Pasquale Joseph Federico|series= Sources in the History of Mathematics and Physical Sciences|volume=4|publisher=Springer|year=1982|page=118}}</ref>