Genady

This is not true.

OK, then [math]\frac{xy}{2}=\frac{1}{\sin 2\beta}[/math].

According to the drawing, the radius of the circle is 1. You should've asked me, what is [math]\alpha[/math]. It is an angle between the green line and the axis.

The Riemann curvature tensor in one dimension does not vanish but rather is undefined. It has no components in 1D.

[math]\frac{xy}{2}=\frac{1}{\sin 2 \alpha}[/math]

You are correct. It includes only a finite number of radicals.

On one hand, (notice the very last statement) ... On the other hand, [math]x=\sqrt[5]{2+5\sqrt[5]{2+5\sqrt[5]{2+...}}}[/math] solves that polynomial. What's wrong?

And that's why the OP question is misleading. IOW, a waste of time. P.S. I should've guessed so as it is in The Lounge and not in The Puzzles.

, for our convenience. Another not Fibonacci: 328, 176, 105, 83, ... What are the next terms?

You're right. They are equivalent. This is not a meaningful sequence; the order is arbitrary.

It can be, e.g., [math]F_n=2F_{n-2}+F_{n-3}[/math].

This is a different question, not the one in the OP. I'm sorry you say this.

Yes, but we're not given the next two numbers, so we don't know that it is not fibonacci.

You're asking, why it is not a Fibonacci sequence, but it looks like a Fibonacci sequence to me.

It was for a different sequence, before the OP edit, so I deleted it.