find the closed form of generating function such that $x^1+x^4 + x^9 +x^{16} +x^{25} +...+x^{n^2}+....$
92754
Closed form for the series: $\sum_{n=1}^{\infty}x^{n^2}$
43320
Find the sum of the power series $\sum_{n=1}^\infty n*(n+1)*x^n$
128496
Find the coefficient of $x^9$ in the expansion of $(1+x)(1+x^2)(1+x^3)...(1+x^{100})$
19914
Closed form for $\sum_{n=0}^{\infty} \binom{n+k}{k} x^n$ (Negative Binomial Theorem)
53246
The limit of the alternating series $x - x^2 + x^4 - x^8 + {x^{16}}-\dotsb$ as $x \to 1$
143236
$ S_{n}=\frac{x}{x+1}+\frac{x^2}{(x+1)(x^2+1)}+...........+\frac{x^{2^{n}}}{(x+1)(x^2+1)...(x^{2^{n}}+1)}$
45862
Nested sum of binomial coefficient in closed form
12423
"Closed" form for $\sum \frac{1}{n^n}$
113189
Find the sum of the series $1^2-2^2+3^2-4^2+...-(2n)^2$
99502
Question on the coefficients of $(1+x+x^2+x^3+x^4)^{496}$
158004
A formula for $1^4+2^4+...+n^4$
123507
How to find the closed form of multiplications of exponentials?
157972
Find a closed form expression for $\sum\limits_{i=0}^{\infty} i^2\cdot x^i$
14884
Compute a sum with partial fraction decomposition and generating functions
110441
Closed form for a formula with a summation over $i\binom{n-i}{k-1}$, and combinatorial proof?
71482
Solve $p_4(x) = x^4 −(2m + 4)x^2 + (m−2)^2 $such that $p_4$ is a product of two non-constant integer-coeficient polynomials
61592
Exponential generating function to find recurrence formula $a_n$