Skip to main content

All Questions

Filter by
Sorted by
Tagged with
35 votes
3 answers
2k views

A binomial generalization of the FLT: Bombieri's Napkin Problem

This is an extract from Apéry's biography (which some of the people have already enjoyed in this answer). During a mathematician's dinner in Kingston, Canada, in 1979, the conversation turned ...
Wadim Zudilin's user avatar
27 votes
1 answer
2k views

Solutions to $\binom{n}{5} = 2 \binom{m}{5}$

In Finite Mathematics by Lial et al. (10th ed.), problem 8.3.34 says: On National Public Radio, the Weekend Edition program posed the following probability problem: Given a certain number of ...
Nick Matteo's user avatar
24 votes
2 answers
2k views

Are (55, 165, 495, 1485) and (286, 1716, 10296, 61776) the only geometric sequences of length 4 among non-trivial binomials?

Let's define non-trivial binomial coefficients as values of $\binom{n}{k}$, where $n$ and $k$ are positive integers such that $2 \le k \le \frac{n}{2}$. (Therefore, $6$ is the smallest non-trivial ...
William Hu's user avatar
1 vote
0 answers
138 views

Eisenstein triples (and triangles with rational sides and a rational-degree angle) in Pascal's triangle

This question leads to a follow-up: are there any Eisenstein triples (satisfying $a^2\pm ab+b^2=c^2$) in one row of Pascal's triangle apart from the following: $\binom{23}{8}^2+\binom{23}{8}\binom{23}{...
Oscar Lanzi's user avatar
  • 2,370
0 votes
2 answers
2k views

non negative integer solutions : Diophantine Equations [closed]

I want to know the exact number of non-negative integer solutions of $a_1 + 2a_2 + \ldots + k \cdot a_k = n$. I know that it is the co-efficient of $x^n$ in $(1 - x^{a_1})^{-1} \cdot (1 - x^{a_2})^{-...
Sai Nikhil's user avatar