A Centered Polygonal Number Identity

Summary

We illustrate the identity $C_{n,n+2}=C_{n+2,n+1}$, where $C_{k,n}$ denotes the $n^{\text{th}}$ k-gonal number.

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Additional information

Notes on contributors

Roger B. Nelsen

ROGER NELSEN (MR Author ID: 237909) is a professor emeritus at Lewis & Clark College, where he taught mathematics and statistics for 40 years.