User RobPratt - Mathematics Stack Exchange

5 votes

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Probability of choosing cards from a standard deck of 52

answered Aug 13, 2020 at 3:48

5 votes

Find a generating function involving a tiling problem

answered Mar 7, 2020 at 23:23

5 votes

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Computing the binomial sum $\sum_{0\le i<j\le n}j\binom ni$

answered Apr 6, 2020 at 4:27

5 votes

Notation for set minus

answered May 6, 2020 at 3:55

5 votes

The minimum $N \times N$ square covering problem for $1 \times 4$ shaped tetrominoes

answered Oct 1, 2019 at 1:59

5 votes

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Find the formula for the convolution of the sequences (generating functions)

answered Aug 25, 2019 at 20:55

5 votes

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The sum of fractions of square of binomial coefficient DIVIDED by index variable

answered Jan 7, 2020 at 4:52

5 votes

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Doing a Charnes-Cooper transformation with matrices and an zero-one constraint

answered Jan 7, 2020 at 16:45

5 votes

Max packing of cars in square parking lot

answered Jan 5, 2020 at 22:24

5 votes

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What combination of inputs results in the largest output?

answered Jan 26, 2020 at 17:31

5 votes

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Explain how $\sum_{k = 1}^n\frac{k^2}{2^{k - 1}} = \sum_{k = 0}^{n - 1}\frac{\left(k + 1\right)^2}{2^k}$?

answered Jan 26, 2020 at 17:46

4 votes

Number of ways a committee could be formed if Mr $A$ refuses to serve on the committee if Ms $B$ is a member

answered Jan 2, 2020 at 14:22

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How should I solve combination addition like this?

answered Jan 12, 2020 at 15:48

4 votes

Maximum number of students such that they all have at least 3 out of 6 different answers.

answered Jan 17, 2020 at 0:27

4 votes

Minimum number of dominoes on an $n \times n$ chessboard to prevent placement of another domino.

answered Jan 24, 2020 at 2:02

4 votes

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Intersections between two columns of equal number points

answered Aug 24, 2019 at 20:28

4 votes

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Construct $b_n$ so that $\sum_{n=0}^{\infty}b_n=B$

answered Aug 19, 2019 at 18:50

4 votes

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Guaranteed to guess two numbers in one from twelve lottery tickets, if falls $6$ balls with numbers from $1$ to $36$

answered Jun 29, 2019 at 14:07

4 votes

What is the pattern in this set {2, 3, 4, 6, 8, 9, 12, 16, 18, 24, ...}?

answered Sep 18, 2019 at 18:57

4 votes

How many bit strings of length 8 have a weight of 5 start with 101 OR end with 11.

answered Oct 7, 2019 at 19:55

4 votes

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Algebraic proof of $\sum_{k}\binom{n}{2k}\binom{2k}{k}2^{n-2k}=\binom{2n}n$ (Combinatoric proof is given)

answered Oct 16, 2019 at 19:58

4 votes

Let S = {1, 2, 3, 4}. How many equivalence relation are there and describe them?

answered Oct 25, 2019 at 15:02

4 votes

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what is the value of $\binom{n}{1}+\binom{n}{4}+\binom{n}{7}+\binom{n}{10}+\binom{n}{13}+\dots$

answered Apr 26, 2020 at 5:16

4 votes

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Why are all functions $\{0,1\}^t \rightarrow \{0,1\}$ expressable as polynomials?

answered May 1, 2020 at 17:51

4 votes

Number of ways to color in a $2\times5$ grid

answered Apr 11, 2020 at 2:29

4 votes

Partitions using only powers of two on $1000.$

answered Jul 4, 2020 at 20:48

4 votes

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How to construct a 5-regular graph with diameter 2 on 22 vertices?

answered Jul 5, 2020 at 18:08

4 votes

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Maximum odd number of subsets, each intersects exactly half of the others

answered Mar 14, 2020 at 20:26

4 votes

Solving binomial summation $\sum_{k=0}^{\lfloor{n/2}\rfloor} \binom{n-k}{k} 2^{n-k}$

answered Mar 16, 2020 at 20:17

4 votes

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Are constants allowed within an objective function for a linear programming problem?

answered Mar 28, 2020 at 20:45

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1,968 Answers

Probability of choosing cards from a standard deck of 52

Find a generating function involving a tiling problem

Computing the binomial sum $\sum_{0\le i<j\le n}j\binom ni$

Notation for set minus

The minimum $N \times N$ square covering problem for $1 \times 4$ shaped tetrominoes

Find the formula for the convolution of the sequences (generating functions)

The sum of fractions of square of binomial coefficient DIVIDED by index variable

Doing a Charnes-Cooper transformation with matrices and an zero-one constraint

Max packing of cars in square parking lot

What combination of inputs results in the largest output?

Explain how $\sum_{k = 1}^n\frac{k^2}{2^{k - 1}} = \sum_{k = 0}^{n - 1}\frac{\left(k + 1\right)^2}{2^k}$?

Number of ways a committee could be formed if Mr $A$ refuses to serve on the committee if Ms $B$ is a member

How should I solve combination addition like this?

Maximum number of students such that they all have at least 3 out of 6 different answers.

Minimum number of dominoes on an $n \times n$ chessboard to prevent placement of another domino.

Intersections between two columns of equal number points

Construct $b_n$ so that $\sum_{n=0}^{\infty}b_n=B$

Guaranteed to guess two numbers in one from twelve lottery tickets, if falls $6$ balls with numbers from $1$ to $36$

What is the pattern in this set {2, 3, 4, 6, 8, 9, 12, 16, 18, 24, ...}?

How many bit strings of length 8 have a weight of 5 start with 101 OR end with 11.

Algebraic proof of $\sum_{k}\binom{n}{2k}\binom{2k}{k}2^{n-2k}=\binom{2n}n$ (Combinatoric proof is given)

Let S = {1, 2, 3, 4}. How many equivalence relation are there and describe them?

what is the value of $\binom{n}{1}+\binom{n}{4}+\binom{n}{7}+\binom{n}{10}+\binom{n}{13}+\dots$

Why are all functions $\{0,1\}^t \rightarrow \{0,1\}$ expressable as polynomials?

Number of ways to color in a $2\times5$ grid

Partitions using only powers of two on $1000.$

How to construct a 5-regular graph with diameter 2 on 22 vertices?

Maximum odd number of subsets, each intersects exactly half of the others

Solving binomial summation $\sum_{k=0}^{\lfloor{n/2}\rfloor} \binom{n-k}{k} 2^{n-k}$

Are constants allowed within an objective function for a linear programming problem?