User Empy2

25 votes

1 answer

782 views

Fibonacci-related sum

asked Jan 9, 2015 at 11:18

14 votes

1 answer

730 views

Narcissistic numbers in other bases

number-theory arithmetic-combinatorics

asked Jun 21, 2013 at 2:40

9 votes

1 answer

461 views

Guess the number of a liar

game-theory

asked May 17, 2014 at 13:36

9 votes

1 answer

175 views

Binomial sum gives $4^n$

binomial-coefficients

asked Jan 1, 2016 at 1:08

8 votes

2 answers

1k views

Rearrangement of dinner guests

combinatorics graph-theory

asked Jun 10, 2013 at 17:31

7 votes

1 answer

208 views

How many ways to reach an integer by addition and multiplication

sequences-and-series combinatorics

asked Jan 24 at 12:03

5 votes

1 answer

84 views

Sum of factors from consecutive sequence

elementary-number-theory

asked Aug 31, 2016 at 5:21

5 votes

1 answer

4k views

Number of normals from a point to an ellipse

geometry conic-sections

asked Dec 16, 2013 at 17:43

4 votes

2 answers

583 views

Circumradius of a tetrahedron

geometry reference-request

asked Jun 15, 2018 at 2:19

4 votes

0 answers

151 views

$Z_n \backslash \{0\}$ splits into octets

recreational-mathematics

asked Jul 17, 2014 at 5:22

4 votes

0 answers

407 views

Split $\{1,2,...,3n\}$ into triples with $x+y=4z$

combinatorics elementary-number-theory combinatorial-designs

asked Jul 4, 2021 at 16:15

3 votes

0 answers

126 views

Hypercube bisector: Does this alternating sum have a limit?

sequences-and-series limits euclidean-geometry recreational-mathematics

asked Aug 6, 2021 at 14:05

3 votes

1 answer

409 views

Version of Fitch Cheney's card trick

recreational-mathematics card-games

asked Apr 21, 2019 at 16:15

3 votes

1 answer

111 views

What is the dimension of this fractal curve?

geometry fractals

asked Dec 10, 2017 at 8:51

3 votes

1 answer

179 views

How fast does $f_n = \sin f_{n-1}$ approach zero? [duplicate]

sequences-and-series

asked Jun 20, 2013 at 14:36

3 votes

0 answers

107 views

Typical dimension of eigenspace

eigenvalues-eigenvectors nilpotence

asked Jun 4, 2014 at 8:42

3 votes

2 answers

161 views

Lowest score never made

probability

asked Sep 16, 2013 at 14:21

3 votes

2 answers

245 views

seventeen tiles on a torus

combinatorics

asked Jun 24, 2013 at 17:18

2 votes

1 answer

150 views

Average number of $U[0,1]$ random numbers to reach $x$

random

asked Jun 21, 2013 at 17:27

2 votes

1 answer

94 views

Numbers not of the form $x^2+My^2$

arithmetic-combinatorics

asked Jun 13, 2013 at 8:37

2 votes

0 answers

139 views

Smallest prime p with N a quadratic residue mod p

number-theory arithmetic-functions

asked Jun 15, 2013 at 15:19

2 votes

0 answers

417 views

Square pairs in other bases

elementary-number-theory

asked Jun 30, 2013 at 11:49

2 votes

0 answers

74 views

Coloring of small chessboards on the torus

recreational-mathematics coloring chessboard

asked Oct 8, 2020 at 13:06

2 votes

1 answer

83 views

Armstrong numbers in base 90

elementary-number-theory recreational-mathematics

asked Oct 21, 2014 at 7:00

2 votes

0 answers

110 views

Chessboard four-colour theorem

recreational-mathematics chessboard

asked Mar 25, 2016 at 13:01

1 vote

1 answer

87 views

Size of a subset of $\mathbb{N}$

sequences-and-series recurrence-relations recreational-mathematics

asked Oct 4, 2021 at 14:14

1 vote

2 answers

134 views

Split $\{1,...,3n\}$ into triples with $x+y=5z$ - no solutions?

combinatorics elementary-number-theory combinatorial-designs

asked Jul 10, 2021 at 17:30

1 vote

2 answers

137 views

Pointless probability

markov-chains

asked Feb 14, 2016 at 4:33

1 vote

1 answer

40 views

Cubic with turning point near zero

elementary-functions

asked Jul 7, 2013 at 14:03

1 vote

1 answer

155 views

A game theory question about tiles, part 2

probability game-theory

asked Sep 16, 2013 at 14:43

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32 Questions

Fibonacci-related sum

Narcissistic numbers in other bases

Guess the number of a liar

Binomial sum gives $4^n$

Rearrangement of dinner guests

How many ways to reach an integer by addition and multiplication

Sum of factors from consecutive sequence

Number of normals from a point to an ellipse

Circumradius of a tetrahedron

$Z_n \backslash \{0\}$ splits into octets

Split $\{1,2,...,3n\}$ into triples with $x+y=4z$

Hypercube bisector: Does this alternating sum have a limit?

Version of Fitch Cheney's card trick

What is the dimension of this fractal curve?

How fast does $f_n = \sin f_{n-1}$ approach zero? [duplicate]

Typical dimension of eigenspace

Lowest score never made

seventeen tiles on a torus

Average number of $U[0,1]$ random numbers to reach $x$

Numbers not of the form $x^2+My^2$

Smallest prime p with N a quadratic residue mod p

Square pairs in other bases

Coloring of small chessboards on the torus

Armstrong numbers in base 90

Chessboard four-colour theorem

Size of a subset of $\mathbb{N}$

Split $\{1,...,3n\}$ into triples with $x+y=5z$ - no solutions?

Pointless probability

Cubic with turning point near zero

A game theory question about tiles, part 2