I have a problem that might seem quite trivial, but I'm having a hard time getting my head around it:
I have to construct a vector of the form $$\overline{\pi}=[\pi(0),\{\pi(i,j)\}]$$ where $j\in{\mathbb{N}}$ and $i \in \mathcal{A}$, and $\mathcal{A}= \{A,B,C,D,E,F\}$, such that the first entries appear as $$\overline{\pi}=[\pi(0),\pi(A,1),...,\pi(F,1),\pi(A,2),...,\pi(F,2),\pi(A,3),...,\pi(F,3),...]$$ and so on. How do I do this? Given that $$\pi(i,j) = \frac{\pi(0)}{\beta_i}\cdot\frac{1}{j}\left(\frac{\beta_i}{\delta_i}\right)^j,$$ my thoughts was to write $$\overline{\pi} = \left(\pi(0),\left\{\frac{\pi(0)}{\beta_i}\frac{1}{j}\left(\frac{\beta_i}{\delta_i}\right)^j\right\}_{j\in \mathbb{N} ,\ i\in\mathcal{A}}\right)$$but I'm quite sure that the index is wrong. Does anyone have an idea on how to do this? Thanks in advance.