279279

Appears in sequences

• Odd abundant numbers not divisible by 5.at n=8A064001
• Odd admirable numbers: such that sigma(n) = 2n + 2d for some d | n.at n=22A109729
• Odd doubly abundant numbers (A125639).at n=23A129087
• The odd part of those numbers which divide the sum of their divisors (A007691).at n=14A320024
• Numbers k such that k and k+1 are both S-abundant numbers (A181487).at n=29A364861
• Numbers k such that k and k+1 both have at least three divisors with the same value of the Euler totient function (A000010).at n=9A373529
• Denominators of the partial sums of the reciprocals of the unitary totient function (A047994).at n=41A379518
• Odd abundant numbers that are also doublets (cf. A020338).at n=12A380232
• Odd abundant numbers not divisible by 5 that are also doublets (cf. A020338).at n=6A380233
• a(n) is the least number k such that there is a set of n proper divisors of k whose sum is k, and no set of fewer than n proper divisors of k whose sum is k.at n=30A389712