Generalized octagonal numbers are integers of the form $n(3n-2)$ with $n\in\Z$. In this paper we show that every natural number can be written as the sum of four generalized octagonal numbers. This result is similar to Lagrange's theorem on sums of four squares.
How to add two natural numbers in base phi
Sums of four polygonal numbers with coefficients
Almost Universal Weighted Ternary Sums of Polygonal Numbers
![QR code for arXiv:1503.03743 [math.NT]](http://oss.arxitics.com/images/favicon.svg)