1848964

Appears in sequences

• Numbers k such that sigma(k) == 4 (mod k).at n=11A045769
• Numbers n such that sigma(n) = 2n + omega(n), where omega(n) is the number of distinct prime divisors of n.at n=8A063785
• Numbers k such that sigma(k) == 0 (mod k+2).at n=9A067702
• Numbers k whose abundance is 4: sigma(k) - 2*k = 4.at n=8A088832
• Admirable numbers such that the subtracted divisor is prime.at n=13A109766
• Admirable numbers whose abundance is < 10.at n=29A109788
• Near-multiperfects with primes, powers of 2, 6 * prime and 2^n * prime excluded, abs(sigma(n) mod n) <= log(n).at n=32A117350
• (N\{4})-perfect numbers, i.e., numbers m for which sigma(m)-4 = 2m, if 4|m, otherwise sigma(m) = 2m.at n=6A181597
• Admirable numbers such that the subtracted divisor is a Fibonacci number.at n=30A282754
• Nonprime numbers k such that A054008(k) = A054024(k).at n=19A343242
• Primitive abundant numbers k (A071395) whose abundancy index sigma(k)/k has a record low value.at n=20A362053