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May 24 at 19:03 comment added Jorge Zuniga @zy I have placed new high order hypergeometric formulas for $\pi^4,\pi^{-4}$ and $\zeta(5)$ here: mathoverflow.net/questions/471939/…
Apr 25 at 15:08 comment added Y. Zhao @pisco: I am very happy that you shared the proofs to the formulas...more than a suprise for me... BTW, is it possible to prove $\zeta(5)$ is irrational with the formula?
Apr 25 at 14:38 history edited Martin Sleziak CC BY-SA 4.0
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Apr 25 at 14:29 history edited Y. Zhao CC BY-SA 4.0
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Dec 22, 2023 at 10:17 comment added pisco Regarding formulas themselves, all of them are now proved using WZ-type method. For example your last two formulas $786/\pi^4$ and $-380928\zeta(5)$ are proved in arxiv.org/pdf/2312.14051.pdf recently.
Mar 30, 2018 at 15:41 history edited Y. Zhao CC BY-SA 3.0
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Jan 31, 2018 at 18:44 history edited Y. Zhao CC BY-SA 3.0
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Jan 30, 2018 at 23:21 comment added Y. Zhao @TitoPiezasIII: I think I noticed that phenomena either. I believe Borwein brothers had searched for similar formulas(not the upside down version) extensively(but I cannot remember the name of that paper), only to re-discover those formulas discovered by Guillera and Gourevitch.
Jan 30, 2018 at 14:19 comment added Tito Piezas III @zy_: You may like this post on upside down pi formulas.
Jan 25, 2018 at 1:20 comment added Y. Zhao @TitoPiezasIII: I searched for hundreds of rational arguments whose numerator and denominator have small prime factors only, but I have no idea whether there is a systematic way to get all these rational arguments. Maybe an expert on arithmetic geometry will show us what the general theory behind these "identities" should be.
Jan 24, 2018 at 16:42 comment added Tito Piezas III @zy_: Ah, I see it now. Yes, they are beautiful and the $\zeta(5)$ is unexpected. I noticed its argument is $-\frac{1024}{3125} = -\frac{4^5}{5^5}$ so tried to generalize it for $\zeta(7)$ using $-\frac{6^7}{7^7}$. Unfortunately, an integer relations algorithm couldn't find anything.
Jan 24, 2018 at 16:25 comment added Y. Zhao @Tito Piezas: I sent an e-mail to Dr. Guillera on these discoveries. He pointed out to me that the counterpart of these three formulas has already been in his paper(formula (34)(36)(37)). He knows the upside-down version of these formulas as well. But the formulas for $1/\pi^4$,$\zeta(4)$ and $\zeta(5)$ are new to him.
Jan 23, 2018 at 17:43 comment added Tito Piezas III @zy_: Are you sure those three formulas for $\zeta(3)$ are in the paper cited? I am unable to find it.
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Sep 24, 2017 at 8:41 comment added ypercubeᵀᴹ Is the ! in $... = -1792\zeta(3)!$ intended or a typo?
Sep 23, 2017 at 18:50 history edited Y. Zhao CC BY-SA 3.0
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Sep 21, 2017 at 13:49 answer added Will Sawin timeline score: 12
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Sep 17, 2017 at 4:20 history edited Y. Zhao CC BY-SA 3.0
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Sep 13, 2017 at 22:34 comment added post.as.a.guest In the latest Magma Handbook, Watkins also tested Guillera's (96) (over ${\bf Q}(\sqrt 5)$) numerically, again finding it to seem to have a $\zeta$-factor in the $L$-function. Zudilin would be the best person to ask about the HGM connection.
Sep 13, 2017 at 16:15 history edited Y. Zhao CC BY-SA 3.0
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Sep 12, 2017 at 22:38 history asked Y. Zhao CC BY-SA 3.0