861630domain: NAppears in sequencesUnitary barely 3-abundant: numbers m such that 3 < usigma(m)/m < usigma(k)/k for all numbers k < m, where usigma is the sum of unitary divisors function (A034448).at n=25A336671Expansion of Sum_{k>0} (1/(1 - k*x^k)^3 - 1).at n=25A363639