Wah-Wu Chai

activity

20062026

most citedOn rearrangement inequalities for multiple sequences

4 citations · 13 across the 15 of their papers we have counts for

collaborators

Showing 2015Show all

2 papers · 1 filter

math.CO2015★ 1 cited

Permutations $r_{j}$ such that $\sum_{i = 1}^{n} \prod_{j = 1}^{k} r_{j} (i)$ is maximized or minimized

Chai Wah Wu

We consider the problem of finding the set of permutations $r_{j}$ of ${1, \dots, n}$ such that $\sum_{i = 1}^{n} \prod_{j = 1}^{k} r_{j} (i)$ is maximized or minimized. While the set of per…

math.NT2015

On a conjecture regarding primality of numbers constructed from prepending and appending identical digits

Chai Wah Wu

Consider the operation of adding the same number of identical digits to the left and to the right of a number n. In OEIS sequence A090287, it was conjectured that this operation wi…

Permutations rj​ such that ∑i=1n​∏j=1k​rj​(i) is maximized or minimized

On a conjecture regarding primality of numbers constructed from prepending and appending identical digits

Permutations $r_{j}$ such that $\sum_{i = 1}^{n} \prod_{j = 1}^{k} r_{j} (i)$ is maximized or minimized