Factor polynomial y^16-1

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                                |    \/ 2    I*\/ 2 | |    \/ 2    I*\/ 2 | |      \/ 2    I*\/ 2 | |      \/ 2    I*\/ 2 | |       /  1   \/ 2          /  1   \/ 2  | |       /  1   \/ 2          /  1   \/ 2  | |         /  1   \/ 2          /  1   \/ 2  | |         /  1   \/ 2          /  1   \/ 2  | |       /  1   \/ 2          /  1   \/ 2  | |       /  1   \/ 2          /  1   \/ 2  | |         /  1   \/ 2          /  1   \/ 2  | |         /  1   \/ 2          /  1   \/ 2  |
(x + 1)*(x - 1)*(x + I)*(x - I)*|x + ----- + -------|*|x + ----- - -------|*|x + - ----- + -------|*|x + - ----- - -------|*|x +   /   - - -----  + I*  /   - + ----- |*|x +   /   - - -----  - I*  /   - + ----- |*|x + -   /   - - -----  + I*  /   - + ----- |*|x + -   /   - - -----  - I*  /   - + ----- |*|x +   /   - + -----  + I*  /   - - ----- |*|x +   /   - + -----  - I*  /   - - ----- |*|x + -   /   - + -----  + I*  /   - - ----- |*|x + -   /   - + -----  - I*  /   - - ----- |
                                \      2        2   / \      2        2   / \        2        2   / \        2        2   / \    \/    2     4        \/    2     4   / \    \/    2     4        \/    2     4   / \      \/    2     4        \/    2     4   / \      \/    2     4        \/    2     4   / \    \/    2     4        \/    2     4   / \    \/    2     4        \/    2     4   / \      \/    2     4        \/    2     4   / \      \/    2     4        \/    2     4   /

$$\left(x - 1\right) \left(x + 1\right) \left(x + i\right) \left(x - i\right) \left(x + \left(\frac{\sqrt{2}}{2} + \frac{\sqrt{2} i}{2}\right)\right) \left(x + \left(\frac{\sqrt{2}}{2} - \frac{\sqrt{2} i}{2}\right)\right) \left(x + \left(- \frac{\sqrt{2}}{2} + \frac{\sqrt{2} i}{2}\right)\right) \left(x + \left(- \frac{\sqrt{2}}{2} - \frac{\sqrt{2} i}{2}\right)\right) \left(x + \left(\sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}} + i \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}}\right)\right) \left(x + \left(\sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}} - i \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}}\right)\right) \left(x + \left(- \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}} + i \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}}\right)\right) \left(x + \left(- \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}} - i \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}}\right)\right) \left(x + \left(\sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}} + i \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}\right)\right) \left(x + \left(\sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}} - i \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}\right)\right) \left(x + \left(- \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}} + i \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}\right)\right) \left(x + \left(- \sqrt{\frac{\sqrt{2}}{4} + \frac{1}{2}} - i \sqrt{\frac{1}{2} - \frac{\sqrt{2}}{4}}\right)\right)$$

(((((((((((((((x + 1)*(x - 1))*(x + i))*(x - i))*(x + sqrt(2)/2 + i*sqrt(2)/2))*(x + sqrt(2)/2 - i*sqrt(2)/2))*(x - sqrt(2)/2 + i*sqrt(2)/2))*(x - sqrt(2)/2 - i*sqrt(2)/2))*(x + sqrt(1/2 - sqrt(2)/4) + i*sqrt(1/2 + sqrt(2)/4)))*(x + sqrt(1/2 - sqrt(2)/4) - i*sqrt(1/2 + sqrt(2)/4)))*(x - sqrt(1/2 - sqrt(2)/4) + i*sqrt(1/2 + sqrt(2)/4)))*(x - sqrt(1/2 - sqrt(2)/4) - i*sqrt(1/2 + sqrt(2)/4)))*(x + sqrt(1/2 + sqrt(2)/4) + i*sqrt(1/2 - sqrt(2)/4)))*(x + sqrt(1/2 + sqrt(2)/4) - i*sqrt(1/2 - sqrt(2)/4)))*(x - sqrt(1/2 + sqrt(2)/4) + i*sqrt(1/2 - sqrt(2)/4)))*(x - sqrt(1/2 + sqrt(2)/4) - i*sqrt(1/2 - sqrt(2)/4))