How to calculate sum of power series

i cant get the code the work

im trying to write a(n+2)=(a(n+1)a(n+1)-b*a*n-2)/(n+2)(n+1)

but the variable a and b are tripping me up

and this error keep coming up

Error: Invalid expression. When calling a function or

indexing a variable, use parentheses. Otherwise, check

for mismatched delimiters.

n=5;

for i=1:n

p=(((a*n+1*a*n+1-b*a*n-2)/(n+2*n+1);

end

[Ameer Hamza]

It seems that the there are mistakes in expression

a(n+2)=(a(n+1)a(n+1)-b*a*n-2)/(n+2)(n+1)

can you show from where did you get this series? Is there a known name for this? Can you attach the original source for this series.

Answer 1

[KSSV]

n=5;
a = rand ;
b = rand ;
p = 0 ;
for i=1:n
    p=p+ (a*n+1*a*n+1-b*a*n-2)/(n+2*n+1);   % check the expression though
end