43873
domain: N
Appears in sequences
- Counterbalanced numbers: Composite numbers k such that phi(k)/(sigma(k)-k) is an integer.at n=31A055940
- a(n) = sigma_4(n^2)/sigma_2(n^2).at n=14A084218
- a(n) = floor(sqrt(a(n-1)^2 + a(n-2)^2)), a(1)=10, a(2)=30.at n=32A104863
- Numbers n such that 10^n - 41 is prime.at n=19A178406
- Numbers n such that 2^(sigma(n)-n) == 1 (mod n).at n=5A277172
- MM-numbers of labeled simple hypergraphs with no singletons spanning an initial interval of positive integers.at n=39A320463
- MM-numbers of crossing, capturing multiset partitions (with empty parts allowed).at n=34A326259
- Positive integers k such that 2^(k+2) - 1 is divisible by k.at n=6A381010