815634435
domain: N
Appears in sequences
- Numbers k such that 2*k+1 is the next prime after sigma(k).at n=10A067795
- Odd numbers m whose abundance by absolute value is at most 10, that is, -10 <= sigma(m) - 2m <= 10.at n=13A077374
- Odd numbers m such that 2*m - sigma(m) = 6.at n=4A087485
- Odd solutions to abs(sigma(k) - 2k) <= log(k). Numbers k whose abundance-radius does not exceed log(k).at n=5A088012
- Numbers k whose deficiency is 6.at n=7A141548
- Odd numbers whose abundancy is closer to 2 than any smaller odd number.at n=23A171929
- Odd deficient numbers whose abundancy is closer to 2 than any smaller odd deficient number.at n=20A188597
- Deficient numbers with increasing abundancy without being powers of 2.at n=21A228450
- Numbers k such that sigma(k) == 0 (mod k-3).at n=12A274552
- Unitary barely deficient numbers: unitary deficient numbers k such that usigma(k)/k > usigma(m)/m for all unitary deficient numbers m < k, where usigma(k) is the sum of the unitary divisors of k (A034448).at n=23A302572
- Positive numbers n for which A000120(n) = k*A294898(n), with k < 0; numbers for which A326130(n) = sigma(n) - A005187(n).at n=12A326131
- Numbers k such that A005187(k) < sigma(k) <= 2k, where A005187(k) = 2k - {binary weight of k}.at n=14A326138
- Infinitary barely deficient numbers: infinitary deficient numbers whose infinitary abundancy is closer to 2 than that of any smaller infinitary deficient number.at n=28A336252
- Numbers m such that sigma(m) = 2*m - omega(m), where omega(m) is the number of distinct prime divisors of m.at n=32A392668