I'm looking for two different sequences that satisfy $x_n=x_{2n}+x_{2n+1}$ for all $n\geq 1$, whats a general possible way to find such sequences/ what other sequences satisfy that condition?
my idea: $x_n = \{0,0,0, \dots ,0\}$
and another im having trouble describing. it goes something like this:
$x_n = \{1, \frac{1}{2}, \frac{1}{2},\frac{1}{4},\frac{1}{4},\frac{1}{4},\frac{1}{4},\underbrace{\frac{1}{8},\dots,\frac{1}{8}}_\text{8 of them}, \underbrace{\frac{1}{16},\dots,\frac{1}{16}}_\text{16 of them} \dots\}$
$x_n=x_{2n}+x_{2n+1}$ is a very loose condition; it leaves a great deal of freedom. Both your examples are fine, but there are more such sequences. In fact, there are immensely many.
In general, it goes like this:
$\dots$