Evaluation of Tachiya's algebraic infinite products involving Fibonacci and Lucas numbers

Abstract

In 2007, Tachiya gave necessary and sufficient conditions for the transcendence of certain infinite products involving Fibonacci numbers $F_k$ and Lucas numbers $L_k$. In the present note, we explicitly evaluate two classes of his algebraic examples. Special cases are$$\prod_{n=1}^{\infty}(1+\frac{1}{F_{2^n+1}})=\frac{3}{\phi}, \qquad \prod_{n=1}^{\infty}(1+\frac{1}{L_{2^n+1}})=3-\phi\, ,$$where $\phi=(1+\sqrt{5})/2$ is the golden ratio.