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((n+1)^n*3^(2n-1))/(2n+1)!

Sum of series ((n+1)^n*3^(2n-1))/(2n+1)!



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The solution

You have entered [src]
  oo                   
____                   
\   `                  
 \           n  2*n - 1
  \   (n + 1) *3       
  /   -----------------
 /        (2*n + 1)!   
/___,                  
n = 1                  
$$\sum_{n=1}^{\infty} \frac{3^{2 n - 1} \left(n + 1\right)^{n}}{\left(2 n + 1\right)!}$$
Sum(((n + 1)^n*3^(2*n - 1))/factorial(2*n + 1), (n, 1, oo))
The radius of convergence of the power series
Given number:
$$\frac{3^{2 n - 1} \left(n + 1\right)^{n}}{\left(2 n + 1\right)!}$$
It is a series of species
$$a_{n} \left(c x - x_{0}\right)^{d n}$$
- power series.
The radius of convergence of a power series can be calculated by the formula:
$$R^{d} = \frac{x_{0} + \lim_{n \to \infty} \left|{\frac{a_{n}}{a_{n + 1}}}\right|}{c}$$
In this case
$$a_{n} = \frac{3^{2 n - 1} \left(n + 1\right)^{n}}{\left(2 n + 1\right)!}$$
and
$$x_{0} = 0$$
,
$$d = 0$$
,
$$c = 1$$
then
$$1 = \lim_{n \to \infty}\left(3^{- 2 n - 1} \cdot 3^{2 n - 1} \left(n + 1\right)^{n} \left(n + 2\right)^{- n - 1} \left|{\frac{\left(2 n + 3\right)!}{\left(2 n + 1\right)!}}\right|\right)$$
Let's take the limit
we find
False

False
The rate of convergence of the power series
The answer [src]
  oo                    
____                    
\   `                   
 \     -1 + 2*n        n
  \   3        *(1 + n) 
  /   ------------------
 /        (1 + 2*n)!    
/___,                   
n = 1                   
$$\sum_{n=1}^{\infty} \frac{3^{2 n - 1} \left(n + 1\right)^{n}}{\left(2 n + 1\right)!}$$
Sum(3^(-1 + 2*n)*(1 + n)^n/factorial(1 + 2*n), (n, 1, oo))
Numerical answer [src]
23.5475627744366503684926149473
23.5475627744366503684926149473
The graph
Sum of series ((n+1)^n*3^(2n-1))/(2n+1)!

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