New posts in conjectures

there exist infinite many $n\in\mathbb{N}$ such that $S_n-[S_n]<\frac{1}{n^2}$

a conjectured continued fraction for $\tan\left(\frac{z\pi}{4z+2n}\right)$

A Simple Calculus view on Fermat's Last Theorem

Any odd number is of form $a+b$ where $a^2+b^2$ is prime

A conjectural closed form for $\sum\limits_{n=0}^\infty\frac{n!\,(2n)!}{(3n+2)!}$

On the problem of polynomial bijection from $\mathbb Q\times\mathbb Q$ to $\mathbb Q$

How can I prove this closed form for $\sum_{n=1}^\infty\frac{(4n)!}{\Gamma\left(\frac23+n\right)\,\Gamma\left(\frac43+n\right)\,n!^2\,(-256)^n}$

Does $|n^2 \cos n|$ diverge to $+\infty$?

Conjectured value of a harmonic sum $\sum_{n=1}^\infty\left(H_n-\,2H_{2n}+H_{4n}\right)^2$

Is $29$ the only prime of the form $p^p+2$?

Conjecture $_2F_1\left(\frac14,\frac34;\,\frac23;\,\frac13\right)=\frac1{\sqrt{\sqrt{\frac4{\sqrt{2-\sqrt[3]4}}+\sqrt[3]{4}+4}-\sqrt{2-\sqrt[3]4}-2}}$

Integral $\int_1^\infty\frac{\operatorname{arccot}\left(1+\frac{2\pi}{\operatorname{arcoth}x-\operatorname{arccsc}x}\right)}{\sqrt{x^2-1}}\mathrm dx$

Conjectures (or intuitions) that turned out wrong in an interesting or useful way

Erdős-Straus conjecture

Conjectured formula for the Fabius function

Conjecture $\int_0^1\frac{dx}{\sqrt[3]x\,\sqrt[6]{1-x}\,\sqrt{1-x\left(\sqrt{6}\sqrt{12+7\sqrt3}-3\sqrt3-6\right)^2}}=\frac\pi9(3+\sqrt2\sqrt[4]{27})$

Why do mathematicians sometimes assume famous conjectures in their research?

Conjecture $\int_0^1\frac{\mathrm dx}{\sqrt{1-x}\ \sqrt[4]x\ \sqrt[4]{2-x\,\sqrt3}}\stackrel?=\frac{2\,\sqrt2}{3\,\sqrt[8]3}\pi$

Is there any conjecture that has been proved to be solvable/provable but whose direct solution/proof is not yet known?

Open mathematical questions for which we really, really have no idea what the answer is