Question

how can I prove that $p=7,n=2$ is the only solution (sum of divisors)?

score 80 · Answer 1 · 2026-04-12 02:19:25

80

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how can I prove that $p=7,n=2$ is the only solution (sum of divisors)?

Published on 12 Apr 2026 - 2:19

score 92 · Answer 2 · 2026-05-06 09:26:37

92

Views

Prove there are infinitely many positive whole numbers that are NOT of the form $4xy+3x+y$ or $4xy+3x-y$

Published on 06 May 2026 - 9:26

score 1.6k · Answer 3 · 2026-04-15 15:39:18

1.6k

Views

Are there infinitely-many numbers that are both square and triangular?

Published on 15 Apr 2026 - 15:39

score 108 · Answer 4 · 2026-04-16 14:19:04

108

Views

if $d|n$, then $S_2(d) \leq S_2(n)$?

Published on 16 Apr 2026 - 14:19

score 399 · Answer 5 · 2026-05-13 20:42:33

399

Views

Prove that $\forall x\in\mathbb{N}\ \text{ there always exists a prime }p\equiv1 \pmod 6 \text{ s.t. }p|(2x)^2+3;$

Published on 13 May 2026 - 20:42

score 846 · Answer 6 · 2026-05-06 09:24:00

846

Views

$n$ or $2n$ is a sum of three squares

Published on 06 May 2026 - 9:24

score 146 · Answer 7 · 2026-04-24 17:59:28

146

Views

Is it consistent with ZF that there is no uncountable set of algebraically independent reals?

Published on 24 Apr 2026 - 17:59

score 46 · Answer 8 · 2026-04-15 20:57:27

46

Views

Estimation of the last digit of $\frac{\sqrt{m!+1}-1}{10}$

Published on 15 Apr 2026 - 20:57

score 34 · Answer 9 · 2026-05-06 09:22:31

34

Views

Groups/Rings/Fields question on Elementary Number Theory

Published on 06 May 2026 - 9:22

score 180 · Answer 10 · 2026-04-13 22:08:50

180

Views

Euclidean GCD calculation and mod

Published on 13 Apr 2026 - 22:08

score 496 · Answer 11 · 2026-04-16 22:37:31

496

Views

Prime counting function $\phi(x)-c(x)$ vs. $x/\ln(x)$

Published on 16 Apr 2026 - 22:37

score 137 · Answer 12 · 2026-05-10 12:42:51

137

Views

Given $a, b$ coprime integers, show that any factor of $a^2 - 2b^2$ is of the form $c^2 - 2d^2$

Published on 10 May 2026 - 12:42

score 64 · Answer 13 · 2026-05-10 17:08:41

64

Views

Question on the difference between harmonic series.

Published on 10 May 2026 - 17:08

score 211 · Answer 14 · 2026-05-13 02:38:33

211

Views

Is there an option to handle Neumann-series when it diverges? (using infinite-sized Carleman matrices)

Published on 13 May 2026 - 2:38

score 75 · Answer 15 · 2026-05-11 00:52:19

75

Views

Is it true that $(2k+1)(2^{4k+1}+(2k-1)^{4k+1})=a^2+(4k+1)b^2$ has no positive integer solution?

Published on 11 May 2026 - 0:52

List Question

how can I prove that $p=7,n=2$ is the only solution (sum of divisors)?

Prove there are infinitely many positive whole numbers that are NOT of the form $4xy+3x+y$ or $4xy+3x-y$

Are there infinitely-many numbers that are both square and triangular?

if $d|n$, then $S_2(d) \leq S_2(n)$?

Prove that $\forall x\in\mathbb{N}\ \text{ there always exists a prime }p\equiv1 \pmod 6 \text{ s.t. }p|(2x)^2+3;$

$n$ or $2n$ is a sum of three squares

Is it consistent with ZF that there is no uncountable set of algebraically independent reals?

Estimation of the last digit of $\frac{\sqrt{m!+1}-1}{10}$

Groups/Rings/Fields question on Elementary Number Theory

Euclidean GCD calculation and mod

Prime counting function $\phi(x)-c(x)$ vs. $x/\ln(x)$

Given $a, b$ coprime integers, show that any factor of $a^2 - 2b^2$ is of the form $c^2 - 2d^2$

Question on the difference between harmonic series.

Is there an option to handle Neumann-series when it diverges? (using infinite-sized Carleman matrices)

Is it true that $(2k+1)(2^{4k+1}+(2k-1)^{4k+1})=a^2+(4k+1)b^2$ has no positive integer solution?

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