43 Lagrange four squares theorem 25 Important formulas in combinatorics 22 Who first proved the generalization of Bertrand's postulate to (2n,3n) and (3n,4n)? 21 powered partition function generator: 1/2 of them are zeros? 20 Prove $4\sum_{k=1}^{p-1}\frac{(-1)^k}{k^2}\equiv 3\sum_{k=1}^{p-1}\frac{1}{k^2}\pmod{p^2}$

### Reputation (7,093)

 +135 $\pi(x+200)-\pi(x)\leq 50$? +55 Number of solutions of a degree 4 polynomial equation over a finite field +10 $q$-(and other)-analogs for counting index-$n$ subgroups in terms of Homs to $S_n$? +10 Expected order of magnitude of character sums under GRH

### Questions (25)

 24 What's special about the circle problem? 23 Hilbert's Theorem on $L_2$ norm of polynomials in $\mathbb{Z}[X]$ - Explicit construction and a converse? 12 Proof of Cauchy's Theorem from Group Theory - Generalizable? 9 Combinatorial\Probabilistic Proof of Stirling's Approximation 9 Condition for a certain subset being a subgroup

### Tags (82)

 337 nt.number-theory × 43 65 sums-of-squares × 3 121 co.combinatorics × 19 51 additive-combinatorics × 2 114 analytic-number-theory × 20 45 rt.representation-theory × 9 100 reference-request × 19 41 finite-groups × 6 82 prime-numbers × 9 38 gr.group-theory × 8

### Bookmarks (114)

 115 Is the boundary $\partial S$ analogous to a derivative? 106 The number $\pi$ and summation by $SL(2,\mathbb Z)$ 76 Solving algebraic problems with topology 74 Books on music theory intended for mathematicians 72 Sophisticated treatments of topics in school mathematics