# Name this sequence

$W=2+5x+9x^2+14x^3+20x^4+\cdots$

Given $|x|<1$, find the value of the series $W$.

Clarification: $2,5,9,14,20,\ldots$ follows a $2^{\text{nd}}$-degree polynomial function, i.e. their second finite difference is a constant.

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