If the sum of the first $n$ terms of the series $1^2 + 2 \cdot 2^2 + 3^2 + 2 \cdot 4^2 + 5^2 + 2 \cdot 6^2 + \dots$ is $\frac{n(n+1)^2}{2}$ when $n$ is even,what is the sum when $n$ is odd?

  • A
    $\frac{n^2(n+1)}{2}$
  • B
    $\frac{n(n+1)(2n+1)}{6}$
  • C
    $\frac{n(n+1)^2}{2}$
  • D
    $\frac{n^2(n+1)^2}{2}$

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