207370

Appears in sequences

• Numbers m such that DivisorSigma(4*k-2, m) mod m = 0 holds presumably for all k; that is, (4k-2)-power-sums of divisors of m are divisible by m for all k.at n=22A066290
• For every positive integer m, let u(m) = (d(1),d(2),...,d(k)) be the unitary divisors of m. The sequence (a(n)) consists of successive numbers m which d(k)/d(1) + d(k-1)/d(2) + ... + d(k)/d(1) is an integer.at n=24A229996
• Numbers that divide the average of the squares of their aliquot parts.at n=9A255245
• Numbers such that A017666(n) = A017668(n).at n=8A261989
• Number of same-trees of weight n.at n=44A281145
• Number of same-trees of weight n in which all outdegrees are odd.at n=44A300647
• a(n) = (-1)^(n-1) + Sum_{d|n, d>1} a(n/d)^d.at n=44A305572
• Numbers k such that the sum of the squares of the odd divisors of k (A050999) is divisible by k.at n=36A355543