# Questions tagged [integer-sequences]

For questions about sequences of integers. References are often made to the online resource oeis.org.

227 questions
Filter by
Sorted by
Tagged with
194 views

189 views

236 views

### Convergence of rivers of numbers

$\DeclareMathOperator{\river}{river}\DeclareMathOperator{\leadingsum}{ls}\DeclareMathOperator{\digitsum}{ds}\newcommand{\qed}{\square}$A 1999 British Informatics Olympiad question asks about ...
113 views

### Are there infinitely many primes of the form $\frac{3a^2-a}{2}+b^4$?
I was inspired from a theorem due to Iwaniec and Friedlander, see , to ask the following conjecuture involving integers. Conjecture. There are infinitely many prime numbers of the form \frac{3a^...
### Solutions of the equation $\psi(\sigma(n))=2n$, where $\sigma(n)$ is the sum of divisors function and $\psi(n)$ the Dedekind psi function
For integers $m\geq 1$ let $\sigma(m)$ the sum of divisors function $\sum_{1\leq d\mid m}d$ and let $\psi(m)$ the Dedekind psi function (as reference I add the Wikipedia Dedekind psi function), then ...