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Code Fixed, as asked in the question; removed PS that is no longer relevant; I am also leaving comments for the OP.
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user9072
user9072

Are there computer packages which calculate coefficients of generating functions, such as

$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$$

or$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2} \text{ or}$$

$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$$ ?$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)} \; ?$$

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

$$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$$

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

Are there computer packages which calculate coefficients of generating functions, such as

$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$$

or

$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$$ ?

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

$$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$$

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

Are there computer packages which calculate coefficients of generating functions, such as

$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2} \text{ or}$$

$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)} \; ?$$

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

$$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$$

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

Code Fixed, as asked in the question; removed PS that is no longer relevant; I am also leaving comments for the OP.
Source Link

Are there computer packages which calculate coefficients of generating functions, such as

  `$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$`

$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$$

or

  `$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$` ?

$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$$ ?

The effort, to calculate all coefficients e.g. $d_{k,l}$$d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$$N^3$, as they satisfy recursion relations such as

`$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$`

$$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$$

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

P.S.: My LaTeX code does not display properly, no matter what I try. Can someone please correct it and inform me what caused the faulty display. I have tried all kinds of escape tokens around LaTeX with raised or lowered indices.

Are there computer packages which calculate coefficients of generating functions, such as

  `$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$`

or

  `$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$` ?

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

`$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$`

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

P.S.: My LaTeX code does not display properly, no matter what I try. Can someone please correct it and inform me what caused the faulty display. I have tried all kinds of escape tokens around LaTeX with raised or lowered indices.

Are there computer packages which calculate coefficients of generating functions, such as

$$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$$

or

$$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$$ ?

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

$$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$$

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

Source Link

Numerical Determination of Generating Functions from Recursion Relations

Are there computer packages which calculate coefficients of generating functions, such as

  `$D_n(q)=\sum_m d_{m,n}q^m= \frac{1}{\prod_{i=1}^n (1-q^i)^2}$`

or

  `$S_d(q)=\sum_m s_{m,d}q^m = \frac{q^d}{\prod_{i=1}^d (1-q^i)}$` ?

The effort, to calculate all coefficients e.g. $d_{k,l}$ for $k$ and $l$ smaller than $N$ should grow with $N^3$, as they satisfy recursion relations such as

`$d_{m,n} = \sum_{k=0}^{[m/n]}(k+1)d_{m-k\cdot n,n-1}$`

which allow to express each of the $N^2$ coefficients as a sum of at most $N$ terms ($d_{m,1}=m+1$, $d_{0,0}=1$, $d_{m,0}=0$ for $m>0$).

Before I revive my rusty computer knowledge I would like to know whether computer packages such as GAP tackle my problem to solve recursion relations with given initial conditions, save the solutions to files and allow to read them in again if one wants to tackle the next case $N+1$.

P.S.: My LaTeX code does not display properly, no matter what I try. Can someone please correct it and inform me what caused the faulty display. I have tried all kinds of escape tokens around LaTeX with raised or lowered indices.