Symsum not making the calculation

I'm running the following symsum script:

clear all;
clc;

syms n k

S3 = symsum(((2-sqrt(3))^(k-2)+(2-sqrt(3))^(n+2-k)+(2-sqrt(3))^k+(2-sqrt(3))^(n-k))^2, k, 2, n)

But it's not doing the calculation. The output I get is:

S3 =
symsum(((603367941593515/2251799813685248)^k + (603367941593515/2251799813685248)^(n - k) + (603367941593515/2251799813685248)^(n - k + 2) + (603367941593515/2251799813685248)^(k - 2))^2, k, 2, n)
>> 

Any ideas on what may be wrong?

Answer 1

[madhan ravi]

n=10000; % make n and k numerical
k=10000;
S3 = cumsum(((2-sqrt(3))^(k-2)+(2-sqrt(3))^(n+2-k)+(2-sqrt(3))^k+(2-sqrt(3))^(n-k))^2)