English

The plastic number and its generalized polynomial

Number Theory 2018-02-06 v3

Abstract

The polynomial X3X1X^{3}-X-1 has a unique positive root known as plastic number, which is denoted by ρ\rho and is approximately equal to 1.324717951.32471795. In this note we study the zeroes of the generalized polynomial Xkj=0k2XjX^{k}-\sum_{j=0}^{k-2}X^{j} for k3k\geq 3 and prove that its unique positive root λk\lambda_{k} tends to the golden ratio ϕ=1+52\phi=\frac{1+\sqrt{5}}{2} as kk \to \infty. We also derive bounds on λk\lambda_{k} in terms of Fibonacci numbers.

Cite

@article{arxiv.1407.2091,
  title  = {The plastic number and its generalized polynomial},
  author = {Vasileios Iliopoulos},
  journal= {arXiv preprint arXiv:1407.2091},
  year   = {2018}
}

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R2 v1 2026-06-22T04:58:14.703Z